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Configuring load balancing

This section describes how to use the FortiOS server load balancing to load balance traffic to multiple backend servers.

You can configure FortiOS load balancing to intercept incoming traffic with a virtual server and distribute it among one or more backend real servers. By doing so, FortiOS enables multiple real servers to respond as if they were a single device or virtual server. This in turn means that more simultaneous requests can be handled by the servers.

Server load balancing configuration

Traffic can be balanced across multiple backend real servers based on a selection of load balancing methods including static (failover), round robin, weighted to account for different sized servers, or based on the health and performance of the server including round trip time, number of connections. The load balancer can balance layer 7 HTTP, HTTPS, SSL, generic layer 4 TCP, UDP and generic layer 3 IP protocols. Session persistence is supported based on injected HTTP/HTTPS cookies or the SSL session ID.

You can bind up to 8 real servers can to one virtual server. The real server topology is transparent to end users, and the users interact with the system as if it were only a single server with the IP address and port number of the virtual server. The real servers may be interconnected by high-speed LAN or by geographically dispersed WAN. The FortiGate unit schedules requests to the real servers and makes parallel services of the virtual server to appear to involve a single IP address.

There are additional benefits to load balancing. First, because the load is distributed across multiple servers, the service being provided can be highly available. If one of the servers breaks down, the load can still be handled by the other servers. Secondly, this increases scalability. If the load increases substantially, more servers can be added behind the FortiGate unit in order to cope with the increased load.

Load balancing and other FortiOS features

Flow-based and proxy-based security features such as virus scanning, IPS, DLP, application control, and web filtering can be applied to load balanced sessions. This includes SSL offloading and multiplexing. Applying these UTM features to load balancing traffic may reduce load balancing performance.

Authentication is not supported for load balancing sessions. Usually FortiGate load balancing is used to allow public access to services on servers protected by a FortiGate unit. Authentication is not generally not required for this kind of configuration.

Features such web proxying, web caching, and WAN optimization also do not work with load balanced sessions. However, most other features that can be applied by a security policy are supported.

Configuring load balancing from the web-based manager

A virtual server is a specialized firewall virtual IP that performs server load balancing. From the web-based manager you add load balancing virtual server by going to Policy & Objects > Load Balance > Virtual Servers.

Name

Enter the name for the virtual server.

Type

Select the protocol to be load balanced by the virtual server. If you select a general protocol such as IP, TCP, or UDP the virtual server load balances all IP, TCP, or UDP sessions. If you select specific protocols such as HTTP, HTTPS, or SSL you can apply additional server load balancing features such as Persistence and HTTP Multiplexing.

• Select HTTP to load balance only HTTP sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced (usually port 80 for HTTP sessions). You can also select HTTP Multiplex. You can also set Persistence to HTTP Cookie to select cookie-based persistence.
• Select HTTPS to load balance only HTTPS sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced (usually port 443 for HTTPS sessions). You can also select Multiplex HTTP requests/responses. You can also set Persistence to HTTP Cookie to select cookie-based persistence. You can also set Persistence to SSL Session ID.
• Select IMAPS to load balance only IMAPS sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced (usually port 993 for IMAPS sessions). You can also set Persistence to SSL Session ID.
• Select POP3S to load balance only POP3S sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced (usually port 995 for POP3S sessions). You can also set Persistence to SSL Session ID.
• Select SMTPS to load balance only SMTPS sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced (usually port 465 for SMTPS sessions). You can also set Persistence to SSL Session ID.
• Select SSL to load balance only SSL sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced.
• Select TCP to load balance only TCP sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced.
• Select UDP to load balance only UDP sessions with destination port number that matches the Virtual Server Port setting. Change Virtual Server Port to match the destination port of the sessions to be load balanced.
• Select IP to load balance all sessions accepted by the security policy that contains this virtual server.

Interface

Select the virtual server external interface from the list. The external interface is connected to the source network and receives the packets to be forwarded to the destination network.

Virtual Server IP

The IP address of the virtual server. This is an IP address on the external interface that you want to map to an address on the destination network.

Virtual Server Port

Enter the external port number that you want to map to a port number on the destination network. Sessions with this destination port are load balanced by this virtual server.

Load Balance Method

Select the load balancing method used by the virtual server.

Persistence

Configure persistence to make sure that a user is connected to the same server every time they make a request that is part of the same session. Session persistence is supported for HTTP and SSL sessions.

HTTP Multiplexing

Select to use the FortiGate unit to multiplex multiple client connections into a few connections between the FortiGate unit and the real server.

Preserve Client IP

Select to preserve the IP address of the client in the X-Forwarded-For HTTP header. This can be useful if you want log messages on the real servers to the client’s original IP address. If this option is not selected, the header will contain the IP address of the FortiGate unit.

This option appears only if HTTP or HTTS are selected for Type, and is available only if HTTP Multiplexing is selected.

SSL Offloading

Select to accelerate clients’ SSL connections to the server by using the Fortinet FortiGate unit to perform SSL operations, then select which segments of the connection will receive SSL offloading.

Certificate

Select the certificate to use with SSL Offloading. The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.

This option appears only if HTTPS or SSL are selected for Type, and is available only if SSL Offloading is selected.

Health Check

Select which health check monitor configuration will be used to determine a server’s connectivity status.

Configuring load balancing from the CLI

From the CLI you configure load balancing by adding a firewall virtual IP and setting the virtual IP type to server load balance:

config firewall vip

edit Vserver-HTTP-1

set type server-load-balance

...

A virtual server includes a virtual server IP address bound to an interface. The virtual server IP address is the destination address incoming packets to be load balanced and the virtual server is bound to the interface that receives the packets to be load balanced.

For example, if you want to load balance incoming HTTP traffic from the Internet to a group of web servers on a DMZ network, the virtual server IP address is the known Internet IP address of the web servers and the virtual server binds this IP address to the FortiGate interface connected to the Internet.

When you bind the virtual server’s external IP address to a FortiGate unit interface, by default, the network interface responds to ARP requests for the bound IP address. Virtual servers use proxy ARP, as defined in RFC 1027, so that the FortiGate unit can respond to ARP requests on a network for a real server that is actually installed on another network. In some cases you may not want the network interface sending ARP replies. You can use the arp-reply option disable sending ARP replies:

config firewall vip

edit Vserver-HTTP-1

set type server-load-balance

set arp-reply disable

...

The load balancing virtual server configuration also includes the virtual server port. This is the TCP port on the bound interface that the virtual server listens for traffic to be load balanced on. The virtual server can listen on any port.

Load balancing methods

The load balancing method defines how sessions are load balanced to real servers. A number of load balancing methods are available as listed below.

All load balancing methods will not send traffic to real servers that are down or not responding. However, the FortiGate unit can only determine if a real server is not responding by using a health check monitor. You should always add at least one health check monitor to a virtual server or to individual real servers, or load balancing methods may attempt to distribute sessions to real servers that are not functioning.

Source IP Hash

The traffic load is statically spread evenly across all real servers. However, sessions are not assigned according to how busy individual real servers are. This load balancing method provides some persistence because all sessions from the same source address always go to the same real server. However, the distribution is stateless, so if a real server is added or removed (or goes up or down) the distribution is changed and persistence could be lost.

Round Robin

Directs new requests to the next real server, and treats all real servers as equals regardless of response time or number of connections. Dead real servers or non responsive real servers are avoided.

Weighted

Real servers with a higher weight value receive a larger percentage of connections. Set the real server weight when adding a real server.

First Alive

Always directs sessions to the first alive real server. This load balancing schedule provides real server failover protection by sending all sessions to the first alive real server and if that real server fails, sending all sessions to the next alive real server. Sessions are not distributed to all real servers so all sessions are processed by the “first” real server only.

First refers to the order of the real servers in the virtual server configuration. For example, if you add real servers A, B and C in that order, then all sessions always go to A as long as it is alive. If A goes down then sessions go to B and if B goes down sessions go to C. If A comes back up sessions go back to A. Real servers are ordered in the virtual server configuration in the order in which you add them, with the most recently added real server last. If you want to change the order you must delete and re-add real servers in the required order.

Least RTT

Directs sessions to the real server with the least round trip time. The round trip time is determined by a Ping health check monitor and is defaulted to 0 if no Ping health check monitors are added to the virtual server.

Least Session

Directs requests to the real server that has the least number of current connections. This method works best in environments where the real servers or other equipment you are load balancing all have similar capabilities. This load balancing method uses the FortiGate session table to track the number of sessions being processed by each real server. The FortiGate unit cannot detect the number of sessions actually being processed by a real server.

HTTP Host

Load balances HTTP host connections across multiple real servers using the host’s HTTP header to guide the connection to the correct real server.

Session persistence

Use persistence to make sure that a user is connected to the same real server every time they make an HTTP, HTTPS, or SSL request that is part of the same user session. For example, if you are load balancing HTTP and HTTPS sessions to a collection of eCommerce web servers, when a user is making a purchase they will be starting multiple sessions as they navigate the eCommerce site. In most cases all of the sessions started by this user during on eCommerce session should be processed by the same real server. Typically, the HTTP protocol keeps track of these related sessions using cookies. HTTP cookie persistence makes sure that all sessions that are part of the same user session are processed by the same real server

When you configure persistence, the FortiGate unit load balances a new session to a real server according to the load balance method. If the session has an HTTP cookie or an SSL session ID, the FortiGate unit sends all subsequent sessions with the same HTTP cookie or SSL session ID to the same real server. For more information about HTTP and HTTPS persistence, see “HTTP and HTTPS persistence”.

Real servers

Add real servers to a load balancing virtual server to provide the information the virtual server requires to be able to send sessions to the server. A real server configuration includes the IP address of the real server and port number that the real server receives sessions on. The FortiGate unit sends sessions to the real server’s IP address using the destination port number in the real server configuration.

When configuring a real server you can also specify the weight (used if the load balance method is set to weighted) and you can limit the maximum number of open connections between the FortiGate unit and the real server. If the maximum number of connections is reached for the real server, the FortiGate unit will automatically switch all further connection requests other real servers until the connection number drops below the specified limit. Setting Maximum Connections to 0 means that the FortiGate unit does not limit the number of connections to the real server.

Real server active, standby, and disabled modes

By default the real server mode setting is active indicating that the real server is available to receive connections. If the real server is removed from the network (for example, for routine maintenance or because of a hardware or software failure) you can change the mode to standby or disabled. In disabled mode the FortiGate unit no longer sends sessions to the real server.

If a real server is in standby mode the FortiGate also does not send sessions to it unless other real servers added to the same virtual server become unavailable. For example:

• A virtual server that includes two real servers one in active mode and one in standby mode. If the real server in active mode fails, the real server in standby mode is changed to active mode and all sessions are sent to this real server.
• A virtual server includes three real servers, two in active mode and one in standby mode, if one of the real servers in active mode fails, the real server in standby mode is changed to active mode and sessions are load balanced between it and still operating real server. If both real servers in active mode fail, all sessions are sent to the real server in standby mode.

Adding real servers from the web-based manager

To add a real server from the web-based manager go to Policy & Objects > Load Balance > Real Servers.

Virtual Server

Select the virtual server that will send sessions to this real server.

IP Address

Enter the IP address of the real server.

Port

Enter the port number on the destination network to which the external port number is mapped.

Weight

Enter the weight value of the real server. The higher the weight value, the higher the percentage of connections the server will handle. A range of 1‑255 can be used. This option is available only if the associated virtual server’s load balance method is Weighted.

Max Connections

Enter the limit on the number of active connections directed to a real server. A range of 1-99999 can be used. If the maximum number of connections is reached for the real server, the FortiGate unit will automatically switch all further connection requests to another server until the connection number drops below the specified limit.

Setting Maximum Connections to 0 means that the FortiGate unit does not limit the number of connections to the real server.

HTTP Host

Enter the HTTP header for load balancing across multiple real servers. This feature is used for load balancing HTTP host connections across multiple real servers using the host’s HTTP header to guide the connection to the correct real server, providing better load balancing for those specific connections.

Mode

Select a mode for the real server.

Adding real servers from the CLI

To add a real server from the CLI you configure a virtual server and add real servers to it. For example, to add three real servers to a virtual server that load balances UDP sessions on port 8190 using weighted load balancing. For each real server the port is not changed. The default real server port is 0 resulting in the traffic being sent the real server with destination port 8190. Each real sever is given a different weight. Servers with higher weights have a max-connections limit to prevent too many sessions from being sent to them.

config firewall vip

edit Vserver-UDP-1

set type server-load-balance

set server-type udp

set ldb-method weighted

set extip 172.20.120.30

set extintf wan1

set extport 8190

set monitor ping-mon-1

config realservers

edit 1

set ip 10.31.101.30

set weight 100

set max-connections 10000

next

edit 2

set ip 10.31.101.40

set weight 100

set max-connections 10000

next

edit 3

set ip 10.31.101.50

set weight 10

end

end

Health check monitoring

From the FortiGate web-based manager you can go to Policy & Objects > Load Balance > Health Check and configure health check monitoring so that the FortiGate unit can verify that real servers are able respond to network connection attempts. If a real server responds to connection attempts the load balancer continues to send sessions to it. If a real server stops responding to connection attempts the load balancer assumes that the server is down and does not send sessions to it. The health check monitor configuration determines how the load balancer tests the real servers. You can use a single health check monitor for multiple load balancing configurations.

You can configure TCP, HTTP and Ping health check monitors. Usually you would want the health check monitor to use the same protocol for checking the health of the server as the traffic being load balanced to it. For example, for an HTTP load balancing configuration you would normally use an HTTP health check monitor.

For the TCP and HTTP health check monitors you can specify the destination port to use to connect to the real servers. If you set the port to 0, the health check monitor uses the port defined in the real server. This allows you to use the same health check monitor for multiple real servers using different ports. You can also configure the interval, timeout and retry. A health check occurs every number of seconds indicated by the interval. If a reply is not received within the timeout period the health check is repeated every second. If no response is received after the number of configured retires, the virtual server is considered unresponsive, and load balancing will disabling traffic to that real server. The health check monitor will continue to contact the real server and if successful, the load balancer can resume sending sessions to the recovered real server.

The default health check configuration has an interval of 10 seconds, a timeout of 2 seconds and a retry of 3. This means that the health check monitor checks the health of a real server every 10 seconds. If a reply is not received within 2 seconds the health check monitor re-checks the server every second for 3 retries. If no response is received for 2 seconds after the final retry the server is considered unresponsive. This entire process takes a total of 7 seconds to consider a virtual server as unresponsive (2 second timeout + (3 re-checks x 1 second) + 2 second timeout = 7 seconds). Since this health check process is repeated every 10 seconds, a server can be down for a maximum of 10 + 7 = 17 seconds before the health check monitor considers it down.

For HTTP health check monitors, you can add URL that the FortiGate unit connects to when sending a get request to check the health of a HTTP server. The URL should match an actual URL for the real HTTP servers. The URL is optional.

The URL would not usually include an IP address or domain name. Instead it should start with a “/” and be followed by the address of an actual web page on the real server. For example, if the IP address of the real server is 10.31.101.30, the URL “/test_page.htm” causes the FortiGate unit to send an HTTP get request to “http://10.31.101.30/test_page.htm”.

For HTTP health check monitors, you can also add a matched content phrase that a real HTTP server should include in response to the get request sent by the FortiGate unit using the content of the URL option. If the URL returns a web page, the matched content should exactly match some of the text on the web page. You can use the URL and Matched Content options to verify that an HTTP server is actually operating correctly by responding to get requests with expected web pages. Matched content is only required if you add a URL.

For example, you can set matched content to “server test page” if the real HTTP server page defined by the URL option contains the phrase “server test page”. When the FortiGate unit receives the web page in response to the URL get request, the system searches the content of the web page for the matched content phrase.

Name

Enter the name of the health check monitor configuration.

Type

Select the protocol used to perform the health check.

• TCP
• HTTP
• PING

Port

Enter the port number used to perform the health check. If you set the Port to 0, the health check monitor uses the port defined in the real server. This way you can use a single health check monitor for different real servers.

This option does not appear if the Type is PING.

Interval

Enter the number of seconds between each server health check.

URL

For HTTP health check monitors, add a URL that the FortiGate unit uses when sending a get request to check the health of a HTTP server. The URL should match an actual URL for the real HTTP servers. The URL is optional.

The URL would not usually include an IP address or domain name. Instead it should start with a “/” and be followed by the address of an actual web page on the real server. For example, if the IP address of the real server is 10.10.10.1, the URL “/test_page.htm” causes the FortiGate unit to send an HTTP get request to “http://10.10.10.1/test_page.htm”.

This option appears only if Type is HTTP.

Matched Content

For HTTP health check monitors, add a phrase that a real HTTP server should include in response to the get request sent by the FortiGate unit using the content of the URL option. If the URL returns a web page, the Matched Content should exactly match some of the text on the web page. You can use the URL and Matched Content options to verify that an HTTP server is actually operating correctly by responding to get requests with expected web pages. Matched content is only required if you add a URL.

For example, you can set Matched Content to “server test page” if the real HTTP server page defined by the URL option contains the phrase “server test page”. When the FortiGate unit receives the web page in response to the URL get request, the system searches the content of the web page for the Matched Content phrase.

This option appears only if Type is HTTP.

Timeout

Enter the number of seconds which must pass after the server health check to indicate a failed health check.

Retry

Enter the number of times, if any, a failed health check will be retried before the server is determined to be inaccessible.

Load balancing limitations

The following limitations apply when adding virtual IPs, load balancing virtual servers, and load balancing real servers. Load balancing virtual servers are actually server load balancing virtual IPs. You can add server load balance virtual IPs from the CLI.

• Virtual IP External IP Address/Range entries or ranges cannot overlap with each other or with load balancing virtual server Virtual Server IP entries.
• A virtual IP Mapped IP Address/Range cannot be 0.0.0.0 or 255.255.255.255.
• A real server IP cannot be 0.0.0.0 or 255.255.255.255.
• If a static NAT virtual IP External IP Address/Range is 0.0.0.0, the Mapped IP Address/Range must be a single IP address.
• If a load balance virtual IP External IP Address/Range is 0.0.0.0, the Mapped IP Address/Range can be an address range.
• When port forwarding, the count of mapped port numbers and external port numbers must be the same. The web-based manager does this automatically but the CLI does not.
• Virtual IP and virtual server names must be different from firewall address or address group names.

Monitoring load balancing

From the web-based manager you can go to Policy & Objects > Monitor > Load Balance Monitor to monitor the status of configured virtual servers and real server and start or stop the real servers. You can also use the get test ipldb command from the CLI to display similar information.

For each real server the monitor displays health status (up or down), active sessions, round trip time and the amount of bytes of data processed. From the monitor page you can also stop sending new sessions to any real server. When you select to stop sending sessions the FortiGate unit performs of graceful stop by continuing to send data for sessions that were established or persistent before you selected stop. However, no new sessions are started.

Virtual Server

The IP addresses of the existing virtual servers.

Real Server

The IP addresses of the existing real servers.

Health Status

Displays the health status according to the health check results for each real server. A green arrow means the server is up. A red arrow means the server is down.

Mode

The mode of the health check monitor. Can be active, standby, or disabled.

Monitor Events

Display each real server’s up and down times.

Active Sessions

Display each real server’s active sessions.

RTT (ms)

Displays the Round Trip TIme (RTT) of each real server. By default, the RTT is “<1”. This value will change only when ping monitoring is enabled on a real server.

Bytes Processed

Displays the traffic processed by each real server.

Graceful Stop/Start

Select to start or stop real servers. When stopping a server, the FortiGate unit will not accept new sessions but will wait for the active sessions to finish.

Load balancing diagnose commands

You can also use the following diagnose commands to view status information for load balancing virtual servers and real servers:

diagnose firewall vip realserver {down | flush | healthcheck | list | up}

diagnose firewall vip virtual-server {filter | log | real-server | session | stats}

For example, the following command lists and displays status information for all real servers:

diagnose firewall vip virtual-server real-server

 

vd root/0 vs vs/2 addr 10.31.101.30:80 status 1/1

conn: max 0 active 0 attempts 0 success 0 drop 0 fail 0

 

vd root/0 vs vs/2 addr 10.31.101.20:80 status 1/1

conn: max 0 active 0 attempts 0 success 0 drop 0 fail 0

Many of the diagnostic commands involve retrieving information about one or more virtual servers. To control which servers are queried you can define a filter:

diagnose firewall vip virtual-server filter <filter_str>

Where <filter_str> can be:

• clear erase the current filter
• dst the destination address range to filter by
• dst-port the destination port range to filter by
• list display the current filter
• name the vip name to filter by
• negate negate the specified filter parameter
• src the source address range to filter by
• src-port the source port range to filter by
• vd index of virtual domain. -1 matches all

The default filter is empty so no filtering is done.

Logging Diagnostics

The logging diagnostics provide information about two separate features:

diagnose firewall vip virtual-server log {console | filter}

Where

• console {disable | enable} enables or disables displaying the event log messages generated by virtual server traffic on the console to simplify debugging.
• filter sets a filter for the virtual server debug log
• The filter option controls what entries the virtual server daemon will log to the console if diagnose debug application vs level is non-zero. The filtering can be done on source, destination, virtual-server name, virtual domain, and so on:

diagnose firewall vip virtual-server log filter <filter_str>

Where <filter_str> can be

• clear erase the current filter
• dst the destination address range to filter by
• dst-port the destination port range to filter by
• list display the current filter
• name the virtual-server name to filter by
• negate negate the specified filter parameter
• src the source address range to filter by
• src-port the source port range to filter by
• vd index of virtual domain. -1 matches all

The default filter is empty so no filtering is done.

Real server diagnostics

Enter the following command to list all the real servers:

diag firewall vip virtual-server real-server list

In the following example there is only one virtual server called slb and it has two real-servers:

diag firewall vip virtual-server server

vd root/0 vs slb/2 addr 172.16.67.191:80 status 1/1

conn: max 10 active 0 attempts 0 success 0 drop 0 fail 0

http: available 0 total 0

 

vd root/0 vs slb/2 addr 172.16.67.192:80 status 1/1

conn: max 10 active 1 attempts 4 success 4 drop 0 fail 0

http: available 1 total 1

The status indicates the administrative and operational status of the real-server.

• max indicates that the real-server will only allow 10 concurrent connections.
• active is the number of current connections to the server attempts is the total number of connections attempted success is the total number of connections that were successful.
• drop is the total number of connections that were dropped because the active count hit max.
• fail is the total number of connections that failed to complete due to some internal problem (for example, lack of memory).

If the virtual server has HTTP multiplexing enabled then the HTTP section indicates how many established connections to the real-sever are available to service a HTTP request and also the total number of connections.

Basic load balancing configuration example

This section describes the steps required to configure the load balancing configuration shown below. In this configuration a FortiGate-51B unit is load balancing HTTP traffic from the Internet to three HTTP servers on the Internal network. HTTP sessions are accepted at the wan1 interface with destination IP address 172.20.120.121 on TCP port 8080 and forwarded from the internal interface to the web servers. When forwarded the destination address of the sessions is translated to the IP address of one of the web servers.

The load balancing configuration also includes session persistence using HTTP cookies, round-robin load balancing, and TCP health monitoring for the real servers. Ping health monitoring consists of the FortiGate unit using ICMP ping to make sure the web servers can respond to network traffic.

Virtual server and real servers setup

To configure the example load balancing configuration - general configuration steps

1. Add a load balance ping health check monitor.
   A ping health check monitor causes the FortiGate unit to ping the real servers every 10 seconds. If one of the servers does not respond within 2 seconds, the FortiGate unit will retry the ping 3 times before assuming that the HTTP server is not responding.
2. Add a load balance virtual server.
3. Add the three load balance real servers. Include the virtual server in each real server configuration.
4. Add a security policy that includes the load balance virtual server as the destination address.

To configure the example load balancing configuration - web-based manager

1. Go to Policy & Objects > Load Balance > Health Check and add the following health check monitor.

Name	Ping-mon-1
Type	Ping
Interval	10 seconds
Timeout	2 seconds
Retry	3

2. Go to Policy & Objects > Load Balance > Virtual Servers and add virtual server that accepts the traffic to be load balanced.

Name	Vserver-HTTP-1
Type	HTTP
Interface	wan1
Virtual Server IP	172.20.120.121
Virtual Server Port	8080
Load Balance Method	Round Robin
Persistence	HTTP Cookie
HTTP Multiplexing	Do not select
Health Check	Move Ping-mon-1 to the Selected list.

3. Go to Policy & Objects > Load Balance > Real Servers and add the real servers.

Virtual Server	Vserver-HTTP-1
IP Address	10.31.101.30
Port	80
Weight	n/a
Max Connections	0
Mode	Active

 

Virtual Server	Vserver-HTTP-1
IP Address	10.31.101.40
Port	80
Weight	n/a
Max Connections	0
Mode	Active

 

Virtual Server	Vserver-HTTP-1
IP Address	10.31.101.50
Port	80
Weight	n/a
Max Connections	0
Mode	Active

4. Go to Policy & Objects > Policy > IPv4 and add a wan1 to internal security policy that includes the virtual server. This policy also applies an Antivirus profile to the load balanced sessions.

Incoming Interface	wan1
Source Address	all
Outgoing Interface	internal
Destination Address	Vserver-HTTP-1
Schedule	always
Service	ALL
Action	ACCEPT
NAT	Turn on NAT and select Use Destination Interface Address.
Antivirus	Turn ON and select an Antivirus profile.

5. Select OK.

To configure the example load balancing configuration- CLI

1. Use the following command to add a Ping health check monitor.

config firewall ldb-monitor

edit ping-mon-l

set type ping

set interval 10

set timeout 2

set retry 3

end

 

2. Use the following command to add the virtual server that accepts HTTP sessions on port 8080 at the wan1 interface and load balances the traffic to three real servers.

config firewall vip

edit Vserver-HTTP-1

set type server-load-balance

set server-type http

set ldb-method round-robin

set extip 172.20.120.30

set extintf wan1

set extport 8080

set persistence http-cookie

set monitor tcp-mon-1

config realservers

edit 1

set ip 10.31.101.30

set port 80

next

edit 2

set ip 10.31.101.40

set port 80

end

end

 

3. Use the following command to add a security policy that includes the load balance virtual server as the destination address.

config firewall policy

edit 0

set srcintf wan1

set srcaddr all

set dstintf internal

set dstaddr Vserver-HTTP-1

set action accept

set schedule always

set service ALL

set nat enable

set utm-status enable

set profile-protocol-options default

set av-profile scan

end

HTTP and HTTPS load balancing, multiplexing, and persistence

In a firewall load balancing virtual server configuration, you can select HTTP to load balance only HTTP sessions. The virtual server will load balance HTTP sessions received at the virtual server interface with destination IP address that matches the configured virtual server IP and destination port number that matches the configured virtual server port. The default virtual server port for HTTP load balancing is 80, but you can change this to any port number. Similarly for HTTPS load balancing, set the virtual server type to HTTPS and then select the interface, virtual server IP, and virtual server port that matches the HTTPS traffic to be load balanced. Usually HTTPS traffic uses port 443.

You can also configure load balancing to offload SSL processing for HTTPS and SSL traffic. See “SSL offloading” for more information.

HTTP and HTTPS multiplexing

For both HTTP and HTTPS load balancing you can multiplex HTTP requests and responses over a single TCP connection. HTTP multiplexing is a performance saving feature of HTTP/1.1 compliant web servers that provides the ability to pipeline many unrelated HTTP or HTTPS requests on the same connection. This allows a single HTTPD process on the server to interleave and serve multiple requests. The result is fewer idle sessions on the web server so server resources are used more efficiently. HTTP multiplexing can take multiple separate inbound sessions and multiplex them over the same internal session. This may reduce the load on the backend server and increase the overall performance.

HTTP multiplexing may improve performance in some cases. For example, if users web browsers are only compatible with HTTP 1.0. HTTP multiplexing can also improve performance between a web server and the FortiGate unit if the FortiGate unit is performing SSL acceleration. However, in most cases HTTP multiplexing should only be used if enabling it leads to a measurable improvement in performance.

To enable HTTP multiplexing from the web-based manager, select multiplex HTTP requests/responses over a single TCP connection. To enable HTTP multiplexing from the CLI enable the http-multiplex option.

Preserving the client IP address

Select preserve client IP from the web-based manager or enable the http-ip-header option from the CLI to preserve the IP address of the client in the X-Forwarded-For HTTP header. This can be useful in an HTTP multiplexing configuration if you want log messages on the real servers to the client’s original IP address. If this option is not selected, the header will contain the IP address of the FortiGate unit.

Preserving the client IP address but changing the X-Forwarded-For header name

If you select preserve client IP from the web-based manager or enable the http-ip-header option from the CLI you can also change the name of the X-Forwarded-For header to a custom header name. This can be useful if you want to use a custom header name instead of the standard header name.

You can configure changing the header name from the CLI. When http-ip-header is enabled you can add a custom header name to the http-ip-header-name option. If you don’t add a custom header name the X-Forwarded-For header name is maintained.

HTTP and HTTPS persistence

Configure load balancing persistence for HTTP or HTTPS to make sure that a user is connected to the same server every time they make a request that is part of the same session. HTTP cookie persistence uses injected cookies to enable persistence.

When you configure persistence, the FortiGate unit load balances a new session to a real server according to the Load Balance Method. If the session has an HTTP cookie or an SSL session ID, the FortiGate unit sends all subsequent sessions with the same HTTP cookie or SSL session ID to the same real server.

The following example shows how to enable cookie persistence and set the cookie domain to .example.org.

config firewall vip

edit HTTP_Load_Balance

set type server-load-balance

set server-type http

set extport 8080

set extintf port2

set extip 192.168.20.20

set persistence http-cookie

set http-cookie-domain .example.org

config realservers

edit 1

set ip 10.10.10.1

set port 80

next

edit 2

set ip 10.10.10.2

set port 80

next

edit 3

set ip 10.10.10.3

set port 80

end

How HTTP cookie persistence options work

The following options are available for the config firewall vip command when type is set to server-load-balance, server-type is set to http or https and persistence is set to http‑cookie:

http-cookie-domain-from-host

http-cookie-domain

http-cookie-path

http-cookie-generation

http-cookie-age

http-cookie-share

https-cookie-share

When HTTP cookie persistence is enabled the FortiGate unit inserts a header of the following form into each HTTP response unless the corresponding HTTP request already contains a FGTServer cookie:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Max-Age=3600

The value of the FGTServer cookie encodes the server that traffic should be directed to. The value is encoded so as to not leak information about the internal network.

Enable http-cookie-domain-from-host to extract the cookie domain from the host: header in the HTTP request. For example, to restrict the cookie to.server.com, enter:

The generated cookies could have the following form if the Host: header contains exhost.com:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Domain=.exhost.com; Max-Age=3600

For more information, see “HTTP host-based load balancing”.

Use http-cookie-domain to restrict the domain that the cookie should apply to. For example, to restrict the cookie to.server.com, enter:

set http-cookie-domain .server.com

Now all generated cookies will have the following form:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Domain=.server.com; Max-Age=3600

Use http-cookie-path to limit the cookies to a particular path. For example, to limit cookies to the path /sales, enter:

set http-cookie-path /sales

Now all generated cookies will have the following form:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Domain=.server.com; Path=/sales; Max-Age=3600

Use http-cookie-age to change how long the browser caches the cookie. You can enter an age in minutes or set the age to 0 to make the browser keep the cookie indefinitely:

set http-cookie-age 0

Now all generated cookies will have the following form:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Domain=.server.com; Path=/sales

Use http-cookie-generation to invalidate all cookies that have already been generated. The exact value of the generation is not important, only that it is different from any generation that has already been used for cookies in this domain. The simplest approach is to increment the generation by one each time invalidation is required. Since the default is 0, enter the following to invalidate all existing cookies:

set http-cookie-generation 1

Use http-cookie-share {disable | same-ip} to control the sharing of cookies across virtual servers in the same virtual domain. The default setting same-ip means that any FGTServer cookie generated by one virtual server can be used by another virtual server in the same virtual domain. For example, if you have an application that starts on HTTP and then changes to HTTPS and you want to make sure that the same server is used for the HTTP and HTTPS traffic then you can create two virtual servers, one for port 80 (for HTTP) and one for port 443 (for HTTPS). As long as you add the same real servers to both of these virtual servers (and as long as both virtual servers have the same number of real servers with the same IP addresses), then cookies generated by accessing the HTTP server are reused when the application changes to the HTTPS server.

If for any reason you do not want this sharing to occur then select disable to make sure that a cookie generated for a virtual server cannot be used by other virtual servers.

Use https-cookie-secure to enable or disable using secure cookies. Secure cookies are disabled by default because secure cookies can interfere with cookie sharing across HTTP and HTTPS virtual servers. If enabled, then the Secure tag is added to the cookie inserted by the FortiGate unit:

Set-Cookie: FGTServer=E7D01637C4B08E89A6714213A9D85D9C7E4D8158; Version=1; Max-Age=3600; Secure

HTTP host-based load balancing

When configuring HTTP or HTTPS load balancing you can select HTTP host load balancing to load balances HTTP host connections across multiple real servers using the host’s HTTP header to guide the connection to the correct real server. HTTP 1.1 includes the concept of a virtual server which allows a HTTP or HTTPS server with a single external IP address to serve requests for multiple DNS domains by using the mandatory Host: header in a HTTP request to indicate which DNS domain the request is destined for.

FortiOS can load-balance HTTP and HTTPS connections among multiple real servers using the Host: header to guide the connection to the correct real server. The host load balancing method allows a real server to specify a http-host attribute which is the domain name of the traffic for that real server. Each real server can only specify a single domain name. The same domain name can appear in more than one real server but only the first one that is up will be used, any others are purely for redundancy. If the Host: header contains a domain that does not match any http-host entry then the connection will be dropped. A real server with no http-host can be matched by any Host: domain.

For example, consider a FortiGate unit that is load-balancing traffic to three real servers. Traffic for www.example1.com should go to 192.168.2.1, traffic for www.example2.com should go to 192.168.2.2 and traffic to any other domain should go to 192.168.2.3. To enable this configuration you would add a virtual server and set the load balance method to HTTP host. Then you would add three real servers and set the HTTP host of the real server with IP address 192.168.2.1 to www.example1.com, the HTTP host of the real server with IP address 192.168.2.2 to www.example2.com and you would not specify an HTTP host for the third real server.

The configuration of a virtual IP to achieve this result would be:

config firewall vip

edit "http-host-ldb"

set type server-load-balance

set extip 172.16.67.195

set extintf "lan"

set server-type http

set ldb-method http-host

set extport 80

config realservers

edit 1

set http-host "www.example1.com"

set ip 192.168.2.1

set port 80

next

edit 2

set http-host "www.example2.com"

set ip 192.168.2.2

set port 80

next

edit 3

set ip 192.168.2.3

set port 80

next

end

end

Host load balancing and HTTP cookie persistence

In an HTTP host-based load balancing configuration with HTTP cookie persistence enabled you can optionally configure cookie persistence to use the domain set in the host header as the cookie domain. You can do this by enabling the http‑cookie‑domain‑from‑host option, for example:

config firewall vip

edit "http-host-ldb"

set type server-load-balance

set extip 172.16.67.195

set extintf "lan"

set server-type http

set ldb-method http-host

set extport 80

set persistence http-cookie

set http-cookie-domain-from-host enable

config realservers

edit 1

set http-host "www.example1.com"

set ip 192.168.2.1

set port 80

next

edit 2

set http-host "www.example2.com"

set ip 192.168.2.2

set port 80

next

edit 3

set ip 192.168.2.3

set port 80

next

end

end

SSL/TLS load balancing

In a firewall load balancing virtual server configuration, you can select SSL to load balance only SSL and TLS sessions. The virtual server will load balance SSL and TLS sessions received at the virtual server interface with destination IP address that matches the configured virtual server IP and destination port number that matches the configured virtual server port. Change this port to match the destination port of the sessions to be load balanced.

For SSL load balancing you can also set persistence to SSL session ID. Persistence is achieved by the FortiGate unit sending all sessions with the same SSL session ID to the same real server. When you configure persistence, the FortiGate unit load balances a new session to a real server according to the Load Balance Method. If the session has an SSL session ID, the FortiGate unit sends all subsequent sessions with the same SSL session ID to the same real server.

SSL offloading

Use SSL offloading to accelerate clients’ SSL or HTTPS connections to real servers by using the FortiGate unit to perform SSL operations (offloading them from the real servers using the FortiGate unit’s SSL acceleration hardware). FortiGate units can offload SSL 3.0 and TLS 1.0. SSL offloading is available on FortiGate units that support SSL acceleration.

To configure SSL offloading from the web-based manager go to Policy & Objects > Load Balance > Virtual Servers. Add a virtual server and set the type to HTTPS or SSL and select the SSL offloading type (Client <-> FortiGate or Client <-> FortiGate <->Server).

Select Client <-> FortiGate to apply hardware accelerated SSL processing only to the part of the connection between the client and the FortiGate unit. This mode is called half mode SSL offloading. The segment between the FortiGate unit and the server will use clear text communications. This results in best performance, but cannot be used in failover configurations where the failover path does not have an SSL accelerator.

Select Client <-> FortiGate <->Server to apply hardware accelerated SSL processing to both parts of the connection: the segment between client and the FortiGate unit, and the segment between the FortiGate unit and the server. This mode is called full mode SSL offloading. The segment between the FortiGate unit and the server will use encrypted communications, but the handshakes will be abbreviated. This results in performance which is less than the other option, but still improved over communications without SSL acceleration, and can be used in failover configurations where the failover path does not have an SSL accelerator. If the server is already configured to use SSL, this also enables SSL acceleration without requiring changes to the server’s configuration.

SSL Offloading modes

Configuring SSL offloading also requires selecting a certificate to use for the SSL offloading sessions. The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.

The following CLI command shows an example half mode HTTPS SSL offloading configuration. In the example the ssl-mode option sets the SSL offload mode to half (which is the default mode).

config firewall vip

edit Vserver-ssl-offload

set type server-load-balance

set server-type https

set ldb-method round-robin

set extip 172.20.120.30

set extintf wan1

set extport 443

set persistence ssl-session-id

set ssl-mode half

set ssl-certificate my-cert

set monitor t cp-mon-1

config realservers

edit 1

set ip 10.31.101.30

set port 443

next

edit 2

set ip 10.31.101.40

set port 443

end

end

Additional SSL load balancing and SSL offloading options

The following SSL load balancing and SSL offloading options are only available from the CLI:

ssl-client-session-state-max <sessionstates_int>

Enter the maximum number of SSL session states to keep for the segment of the SSL connection between the client and the FortiGate unit.

ssl-client-session-state-timeout <timeout_int>

Enter the number of minutes to keep the SSL session states for the segment of the SSL connection between the client and the FortiGate unit.

ssl-client-session-state-type {both | client | disable | time}

Select which method the FortiGate unit should use when deciding to expire SSL sessions for the segment of the SSL connection between the client and the FortiGate unit.

• both: Select to expire SSL session states when either ssl-client-session-state-max or ssl-client-session-state-timeout is exceeded, regardless of which occurs first.
• count: Select to expire SSL session states when ssl-client-session-state-max is exceeded.
• disable: Select to keep no SSL session states.
• time: Select to expire SSL session states when ssl-client-session-state-timeout is exceeded.

ssl-dh-bits <bits_int>

Enter the number of bits of the prime number used in the Diffie-Hellman exchange for RSA encryption of the SSL connection. Larger prime numbers are associated with greater cryptographic strength.

ssl-http-location-conversion {enable | disable}

Select to replace http with https in the reply’s Location HTTP header field. For example, in the reply, Location: http://example.com/ would be converted to Location: https://example.com/

ssl-http-match-host {enable | disable}

Select to apply Location conversion to the reply’s HTTP header only if the host name portion of Location matches the request’s Host field, or, if the Host field does not exist, the host name portion of the request’s URI. If disabled, conversion occurs regardless of whether the host names in the request and the reply match.

For example, if host matching is enabled, and a request contains Host: example.com and the reply contains Location: http://example.cc/, the Location field does not match the host of the original request and the reply’s Location field remains unchanged. If the reply contains Location: http://example.com/, however, then the FortiGate unit detects the matching host name and converts the reply field to Location: https://example.com/.

This option appears only if ssl-http-location-conversion is enable.

ssl-max-version {ssl-3.0 | tls-1.0 | tls-1.1 | tls-1.2}

Enter the maximum version of SSL/TLS to accept in negotiation. Support TLS 1.2 SSL offloading by specifying tls-1.2.

ssl-min-version {ssl-3.0 | tls-1.0 | tls-1.1 | tls-1.2}

Enter the minimum version of SSL/TLS to accept in negotiation. Support TLS 1.2 SSL offloading by specifying tls-1.2.

ssl-send-empty-frags {enable | disable}

Select to precede the record with empty fragments to thwart attacks on CBC IV. You might disable this option if SSL acceleration will be used with an old or buggy SSL implementation which cannot properly handle empty fragments.

ssl-server-session-state-max <sessionstates_int>

Enter the maximum number of SSL session states to keep for the segment of the SSL connection between the server and the FortiGate unit.

ssl-server-session-state-timeout <timeout_int>

Enter the number of minutes to keep the SSL session states for the segment of the SSL connection between the server and the FortiGate unit. This option appears only if ssl-mode is full.

ssl-server-session-state-type {both | count | disable | time}

Select which method the FortiGate unit should use when deciding to expire SSL sessions for the segment of the SSL connection between the server and the FortiGate unit. This option appears only if ssl-mode is full.

• both: Select to expire SSL session states when either ssl-server-session-state-max or ssl-server-session-state-timeout is exceeded, regardless of which occurs first.
• count: Select to expire SSL session states when ssl-server-session-state-max is exceeded.
• disable: Select to keep no SSL session states.
• time: Select to expire SSL session states when ssl-server-session-state-timeout is exceeded.

SSL offloading support for Internet Explorer 6

In some cases the Internet Explorer 6 web browser may be able to access real servers. To resolve this issue, disable the ssl-send-empty-frags option:

config firewall vip

edit vip_name

set ssl-send-empty-frags disable

end

You can disable this option if SSL acceleration will be used with an old or buggy SSL implementation that cannot properly handle empty fragments.

Disabling SSL/TLS re-negotiation

The vulnerability CVE-2009-3555 affects all SSL/TLS servers that support re-negotiation. FortiOS when configured for SSL/TLS offloading is operating as a SSL/TLS server. The IETF is working on a TLS protocol change that will fix the problem identified by CVE-2009-3555 while still supporting re-negotiation. Until that protocol change is available, you can use the ssl-client-renegotiation option to disable support for SSL/TLS re-negotiation. The default value of this option is allow, which allows an SSL client to renegotiate. You can change the setting to deny to abort any attempts by an SSL client to renegotiate. If you select deny as soon as a ClientHello message indicating a re-negotiation is received from the client FortiOS terminates the TCP connection.

Since SSL offloading does not support requesting client certificates the only circumstance in which a re-negotiation is required is when more than 2^32 bytes of data are exchanged over a single handshake. If you are sure that this volume of traffic will not occur then you can disable re-negotiation and avoid any possibility of the attack described in CVE-2009-3555.

The re-negotiation behavior can be tested using OpenSSL. The OpenSSL s_client application has the feature that the user can request that it do renegotiation by typing “R”. For example, the following shows a successful re-negotiation against a FortiGate unit configured with a VIP for 192.168.2.100:443:

$ openssl s_client -connect 192.168.2.100:443

CONNECTED(00000003)

depth=1 /C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

verify error:num=19:self signed certificate in certificate chain

verify return:0

---

Certificate chain

0

s:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Fortigate/CN=FW80CM3909604325/emailAddress=support@fortinet.com

i:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

1 s:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

i:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

---

Server certificate

-----BEGIN CERTIFICATE-----

 

---certificate not shown---

 

-----END CERTIFICATE-----

subject=/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Fortigate/CN=FW80CM3909604325/emailAddress=support@fortinet.com

issuer=/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

---

No client certificate CA names sent

---

SSL handshake has read 2370 bytes and written 316 bytes

---

New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA

Server public key is 1024 bit

Compression: NONE

Expansion: NONE

SSL-Session:

Protocol : TLSv1

Cipher : DHE-RSA-AES256-SHA

Session-ID:

02781E1E368DCCE97A95396FAA82E8F740F5BBA96CF022F6FEC3597B0CC88095

Session-ID-ctx:

Master-Key:

A6BBBD8477A2422D56E57C1792A4EA9C86F37D731E67D0A66E5CDB2B5C76650780C0E7F01CFF851EC4466186F4C48397

Key-Arg : None

Start Time: 1264453027

Timeout : 300 (sec)

Verify return code: 19 (self signed certificate in certificate

chain)

---

GET /main.c HTTP/1.0

R

RENEGOTIATING

depth=1 /C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

verify error:num=19:self signed certificate in certificate chain

verify return:0

HTTP/1.0 200 ok

Content-type: text/plain

 

/*

* Copyright (C) 2004-2007 Fortinet

*/

 

#include <stdio.h>

#include "vsd_ui.h"

 

int main(int argc, char **argv)

{

return vsd_ui_main(argc, argv);

}

closed

$

The following is the same test, but this time with the VIP configuration changed to ssl-client-renegotation deny:

 

$ openssl s_client -connect 192.168.2.100:443

CONNECTED(00000003)

depth=1 /C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

verify error:num=19:self signed certificate in certificate chain

verify return:0

---

Certificate chain

0

s:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Fortigate/CN=FW80CM3909604325/emailAddress=support@fortinet.com

i:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

1 s:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

i:/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

---

Server certificate

-----BEGIN CERTIFICATE-----

---certificate not shown---

-----END CERTIFICATE-----

subject=/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Fortigate/CN=FW80CM3909604325/emailAddress=support@fortinet.com

issuer=/C=US/ST=California/L=Sunnyvale/O=Fortinet/OU=Certificate

Authority/CN=support/emailAddress=support@fortinet.com

---

No client certificate CA names sent

---

SSL handshake has read 2370 bytes and written 316 bytes

---

New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA

Server public key is 1024 bit

Compression: NONE

Expansion: NONE

SSL-Session:

Protocol : TLSv1

Cipher : DHE-RSA-AES256-SHA

Session-ID:

8253331D266DDE38E4D8A04AFCA9CBDED5B1134932CE1718EED6469C1FBC7474

Session-ID-ctx:

Master-Key:

ED05A3EF168AF2D06A486362FE91F1D6CAA55CEFC38A3C36FB8BD74236BF2657D4701B6C1456CEB5BB5EFAA7619EF12D

Key-Arg : None

Start Time: 1264452957

Timeout : 300 (sec)

Verify return code: 19 (self signed certificate in certificate

chain)

---

GET /main.c HTTP/1.0

R

RENEGOTIATING

19916:error:1409E0E5:SSL routines:SSL3_WRITE_BYTES:ssl handshake failure:s3_pkt.c:530:

Use the following command to check the SSL stats to see that the renegotiations blocked counter is now 1:

diagnose firewall vip virtual-server stats ssl

ssl

client

connections total 0 active 0 max 0

handshakes total 4 active 0 max 0 completed 4 abbreviated 0

session states total 4 active 4 max 4

cipher-suite failures 0

embryonics total 0 active 0 max 0 terminated 0

renegotiations blocked 1

server

connections total 0 active 0 max 0

handshakes total 3 active 0 max 0 completed 2 abbreviated 1

session states total 1 active 1 max 1

cipher-suite failures 0

internal error 0

bad handshake length 0

bad change cipher spec length 0

pubkey too big 0

persistence

find 0 found 0 clash 0 addr 0 error 0

If the virtual server debug log is examined (diagnose debug appl vs -1) then at the point the re-negotiation is blocked there is a log:

vs ssl 12 handshake recv ClientHello

vs ssl 12 handshake recv 1 (0100005403014b5e056c7f573a563bebe0258c3254bbaff7046a461164f34f94f4f3d019c41800002600390038003500160013000a00330032002f0005000400150012000900140011000800060003020100000400230000)

vs ssl 12 client renegotiation attempted rejected, abort

vs ssl 12 closing 0 up

vs src 12 close 0 in

vs src 12 error closing

vs dst 14 error closing

vs dst 14 closed

vs ssl 14 close

vs sock 14 free

vs src 12 closed

vs ssl 12 close

vs sock 12 free

IP, TCP, and UDP load balancing

You can load balance all IP, TCP or UDP sessions accepted by the security policy that includes a load balancing virtual server with the type set to IP, TCP, or UDP. Traffic with destination IP and port that matches the virtual server IP and port is load balanced. For these protocol-level load balancing virtual servers you can select a load balance method and add real servers and health checking. However, you can’t configure persistence, HTTP multiplexing and SSL offloading.