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Services and TCP ports

There are a number of different services and protocols in use on the Internet. The most commonly known is HTTP which is used by web servers to transmit requests and responses for unencrypted web pages. These services are set up to listen for requests on a numbered port. These services and protocols can use any port from 1 to 65,535. To keep things simple for everyone a large number of the more commonly used services started using a standardized list of ports. For instance, though it is not required, by default, most web servers listen for HTTP requests on port 80 and by default, web browsers will send HTTP traffic to port 80. If you wish to use another port such as 8080 you would put “:8080” at the end of the URL to indicate that you want the browser to use 8080 instead of the default port.

Example

Default URL for HTTP traffic when the web server is listening on the standard HTTP port:

http://fortinet.com

URL to the same address when the web server is listening for HTTP traffic on port 8080

http://fortinet.com:8080

Services represent typical traffic types and application packets that pass through the FortiGate unit. Firewall services define one or more protocols and port numbers associated with each service. Security policies use service definitions to match session types. You can organize related services into service groups to simplify your security policy list.

Many well-known traffic types have been predefined on the FortiGate unit. If there is a service that does not appear on the list you can create a service or edit an existing one. You need to know the ports, IP addresses or protocols of that particular service or application uses, to create a service.

Best Practices While you can edit a predefined service it is best to leave those ones alone and create a new service and name it something similar such as the same service name with a descriptive identifier appended. Based on the previous example, instead of the name “HTTP” you could name the service “HTTP8080” or use the application that is using that port, “HTTP-Application”.

Categories

In order to make sorting through the services easier there is a field to categorize the services. The services can be sorted into the following groups:

• Uncategorized
• General
• Web Access
• File Access
• Email
• Network Services
• Authentication
• Remote Access
• Tunnelling
• VoIP, Messaging and Other Applications
• Web Proxy

To create a new category, use the downward pointing arrow next to Create New in the Services window and choose Category. All that will be required is a name for the new category. A comments describing the new category is optional.

Protocol types

One of the fundamental aspects of a service is the type of protocol that use used to define it. When a service is defined one of the following categories of protocol needs to be determined:

• TCP/UDP/SCTP
• ICMP
• ICMP6
• IP

Depending on which of these protocol categories is choose another set of specifications will can also be defined.

TCP/UDP/SCTP

This is the most commonly used service protocol category. Once this category has been selected the other available options to choose are an address, either IP or FQDN, and the protocol and port number.

The protocol will be TCP, UDP or SCTP.

ICMP or ICMP6

When ICMP or ICMP6 is chosen the available options are the ICMP Type and its code.

IP

When IP is the chosen protocol type the addition option is the Protocol Number.

TCP

Transmission Control Protocol (TCP) is one of the core or fundamental protocols of the Internet. It is part of the Transport Layer of the OSI Model. It is designed to provide reliable delivery of data from a program on one device on the network or Internet to another program on another device on the network or Internet. TCP achieves its reliability because it is a connection based protocol. TCP is stream-oriented. It transports streams of data reliably and in order.

TCP establishes a prior connection link between the hosts before sending data. This is often referred to as the handshake. Once the link is established the protocol uses checks to verify that the data transmitted. If an error check fails the data is retransmitted. This makes sure that the data is getting to the destination error free and in the correct order so that it can be put back together into a form that is identical to the way they were sent.

TCP is configured more for reliability than for speed and because of this TCP will likely be slower than a connectionless protocol such as UDP. This is why TCP is generally not used for real time applications such as voice communication or online gaming.

Some of the applications that use TCP are:

• World Wide Web (HTTP and HTTPS)
• Email (SMTP, POP3, IMAP4)
• Remote administration (RDP)
• File transfer (FTP)

UDP

User Datagram Protocol (UDP) like TCP is one of the core protocols of the Internet and part of the Transport Layer of the OSI Model. UDP is designed more for speed than reliability and is generally used for different applications than TCP. UDP sends messages, referred to as datagrams across the network or Internet to other hosts without establishing a prior communication link. In other words, there is no handshake.

UDP is an unreliable service as the datagrams can arrive out of order, duplicated or go missing without any mechanism to verify them. UDP works on the assumption that any error checking is done by the application or is not necessary for the function of the application. This way it avoids the overhead that is required to verify the integrity of the data.

This lack of overhead improves the speed of the data transfer and is why UDP is often used by applications that are time sensitive in nature. UDP's stateless nature is also great for applications that answer a large number of small queries from a large number of clients.

Common uses for UDP are:

• Domain Name Resolution (DNS)
• Time (NTP)
• Streaming media (RTSP, RTP and RTCP)
• Telephone of the Internet (VoIP)
• File Transfer (TFTP)
• Logging (SNMP)
• Online games (GTP and OGP)

SCTP

Stream Control Transmission Protocol (SCTP) is part of the Transport Layer of the OSI Model just like TCP and UDP and provides some of the features of both of those protocols. It is message or datagram orientated like UDP but it also ensures reliable sequential transport of data with congestion control like TCP.

SCTP provides the following services:

• Acknowledged error-free non-duplicated transfer of user data
• Data fragmentation to conform to discovered path MTU size
• Sequenced delivery of user messages within multiple streams, with an option for order-of-arrival delivery of individual user messages
• Optional bundling of multiple user messages into a single SCTP packet
• Network-level fault tolerance through supporting of multi-homing at either or both ends of an association
• Congestion avoidance behavior and resistance to flooding and masquerade attacks

SCTP uses multi-streaming to transport its messages which means that there can be several independent streams of messages traveling in parallel between the points of the transmission. The data is sent out in larger chunks of data than is used by TCP just like UDP but the messages include a sequence number within each message in the same way that TCP does so that the data can be reassembled at the other end of the transmission in the correct sequence without the data having to arrive in the correct sequence.

SCTP is effective as the transport protocol for applications that require monitoring and session-loss detection. For such applications, the SCTP path and session failure detection mechanisms actively monitor the connectivity of the session. SCTP differs from TCP in having multi-homing capabilities at either or both ends and several streams within a connection, typically referred to as an association. A TCP stream represents a sequence of bytes; an SCTP stream represents a sequence of messages.

Some common applications of SCTP include supporting transmission of the following protocols over IP networks:

• SCTP is important in 3G and 4G/LTE networks (for example, HomeNodeB = FemtoCells)
• SS7 over IP (for example, for 3G mobile networks)
• SCTP is also defined and used for SIP over SCTP and H.248 over SCTP
• Transport of Public Switched Telephone Network (PSTN) signaling messages over IP networks.

SCTP is a much newer protocol. It was defined by the IETF Signaling Transport (SIGTRAN) working group in 2000. It was introduced by RFC 3286 and more fully define by RFC 4960.

The FortiGate firewall can apply security policies to SCTP sessions in the same way as TCP and UDP sessions. You can create security policies that accept or deny SCTP traffic by setting the service to “ALL”. FortiOS does not include pre-defined SCTP services. To configure security policies for traffic with specific SCTP source or destination ports you must create custom firewall services for SCTP.

FortiGate units route SCTP traffic in the same way as TCP and UDP traffic. You can configure policy routes specifically for routing SCTP traffic by setting the protocol number to 132. SCTP policy routes can route SCTP traffic according to the destination port of the traffic if you add a port range to the policy route.

You can configure a FortiGate unit to perform stateful inspection of different types of SCTP traffic by creating custom SCTP services and defining the port numbers or port ranges used by those services. FortiGate units support SCTP over IPv4. The FortiGate unit performs the following checks on SCTP packets:

• Source and Destination Port and Verification Tag.
• Chunk Type, Chunk Flags and Chunk Length
• Verify that association exists
• Sequence of Chunk Types (INIT, INIT ACK, etc)
• Timer checking
• Four way handshake checking
• Heartbeat mechanism
• Protection against INIT/ACK flood DoS attacks, and long-INIT flooding
• Protection against association hijacking

FortiOS also supports SCTP sessions over IPsec VPN tunnels, as well as full traffic and event logging for SCTP sessions.

Specific addresses in TCP/UDP/SCTP

In the TCP/UDP/SCTP services it is also possible to set the parameter for a specific IP or Fully Qualified Domain Name address. The IP/FQDN field refers to the destination address of the traffic, not the source. This means for example, that you can set up a custom service that will describe in a policy the TCP traffic over port 80 going to the web site example.com, but you cannot set up a service that describes the TCP traffic over port 80 that is coming from the computer with the address 192.168.29.59.

Protocol port values

The source and destination ports for TCP/UDP/SCTP services are important to get correct. If they are reversed the service will not work. The destination port(s) are the on ones that refer to the ports that the computer will be listening on. These are the port numbers that most people are familiar with when they associate a port number to a protocol. In most cases the source port will be one that is randomly assigned by the computer that is not being already used by another service.

Most people associate HTTP with port 80. This means that a web-server will be listening on port 80 for any http requests being sent to the computer. The computer that is sending the request can use any port that is not already assigned to another service or communication session. There are 65,535 ports that it can randomly assign, but because the ports from 1 to 1024 are normally used for listening for incoming communications it is usually not in that range. It is unless there is a specific instance when you know that a communication will be coming from a predefined source port it is best practice to set the source port range from 1 to 65,535.

ICMP

The Internet Control Message Protocol (ICMP) is a protocol layered onto the Internet Protocol Suite to provide error reporting flow control and first-hop gateway redirection. It is normally used by the operating systems of networked computers to send connectivity status query, response and error messages. It is assigned protocol number 1. There is a version of the protocol for both IPv4 and for IPv6. It is not designed to be absolutely reliable like TCP.

ICMP is not typically used for transporting data or for end-user network applications with the exception of some diagnostic utilities such as ping and traceroute.

ICMP messages are sent in several situations, for example:

• when a datagram cannot reach its destination,
• time exceeded messages
• redirect messages
• when the gateway does not have the buffering capacity to forward a datagram
• when the gateway can direct the host to send traffic on a shorter route.

Some of the specific ICMP message types are:

• ICMP_ECHO
• ICMP_TIMESTAMP
• ICMP_INFO_REQUEST
• ICMP_ADDRESS

For ICMP error messages, only those reporting an error for an existing session can pass through the firewall. The security policy will allow traffic to be routed, forwarded or denied. If allowed, the ICMP packets will start a new session. Only ICMP error messages of a corresponding security policy is available will be sent back to the source. Otherwise, the packet is dropped. That is, only ICMP packets for a corresponding security policy can traverse the FortiGate unit.

ICMP types and codes

ICMP has a number of messages that are identified by the “Type” field. Some of these types have assigned “Code” fields as well. The table below shows the different types of ICMP Types with their associated codes if there are any.

 

ICMP types and codes

Type Number	Type Name	Optional Code(s)
0	Echo Reply
1	Unassigned
2	Unassigned
3	Destination Unreachable	0 Net Unreachable 1 Host Unreachable 2 Protocol Unreachable 3 Port Unreachable 4 Fragmentation Needed and Don't Fragment was Set 5 Source Route Failed 6 Destination Network Unknown 7 Destination Host Unknown 8 Source Host Isolated 9 Communication with Destination Network is Administratively Prohibited 10 Communication with Destination Host is Administratively Prohibited 11 Destination Network Unreachable for Type of Service 12 Destination Host Unreachable for Type of Service 13 Communication Administratively Prohibited 14 Host Precedence Violation 15 Precedence cutoff in effect
4	Source Quench
5	Redirect	0 Redirect Datagram for the Network (or subnet) 1 Redirect Datagram for the Host 2 Redirect Datagram for the Type of Service and Network 3 Redirect Datagram for the Type of Service and Host
6	Alternate Host Address
7	Unassigned
8	Echo
9	Router Advertisement
10	Router Selection
11	Time Exceeded	0 Time to Live exceeded in Transit 1 Fragment Reassembly Time Exceeded
12	Parameter Problem	0 Pointer indicates the error 1 Missing a Required Option 2 Bad Length
13	Timestamp
14	Timestand Reply
15	Information Request
16	Information Reply
17	Address Mask Request
18	Address Mask Reply
19	Reserved (for Security)
20 - 29	Reserved (for Robustness Experiment)
30	Traceroute
31	Datagram Conversion Error
32	Mobile Host Redirect
33	IPv6 Where-Are-You
34	IPv6 I-Am-Here
35	Mobile Registration
36	Mobile Registration Reply
37	Domain Name Request
38	Domain Name Reply
39	SKIP
40	Photuris
41 - 255	Reserved

log-invalid-packet

The log-invalid-packet CLI setting is one that is intended to log invalid ICMP packets. The exact definition being:

If the ForitGate unit receives an ICMP error packet that contains an embedded IP(A,B)|TCP (C,D) header, then if FortiOS can loacate the A:C -> B:D session it checks to make sure that the sequence number in the TCP header is within the range recorded in the session. If the sequence number is not in range then the ICMP packet is dropped.

When this field is enabled, the FortiGate also log messages that are not ICMP error packets.

Types of logs covered by log-invalid-packet

• Invalid ICMP
• If ICMP error message verification (see "check-reset-range") is enabled

• Invalid DNS packets
• DNS packets that contain requests for non-existing domains

• iprope check failed
• reverse path check fail
• denied and broadcast traffic
• no session matched

Some other examples of messages that are not errors that will be logged, based on RFC792:

Type 3 messages correspond to "Destination Unreachable Message"

• Type 3, Code 1 = host unreachable
• Type 3, Code 3 = port unreachable

Type 11 messages correspond to "Time Exceeded Message"

• Type 11, Code 0 = time to live exceeded in transit

ICMPv6

Internet Control Message Protocol version 6 (ICMPv6) is the new implementation of the Internet Control Message Protocol (ICMP) that is part of Internet Protocol version 6 (IPv6). The ICMPv6 protocol is defined in RFC 4443.

ICMPv6 is a multipurpose protocol. It performs such things as:

• error reporting in packet processing
• diagnostic functions
• Neighbor Discovery process
• IPv6 multicast membership reporting

It also designed as a framework to use extensions for use with future implementations and changes.

Examples of extensions that have already been written for ICMPv6:

• Neighbor Discovery Protocol (NDP) - a node discovery protocol in IPv6 which replaces and enhances functions of ARP.
• Secure Neighbor Discovery Protocol (SEND) - an extension of NDP with extra security.
• Multicast Router Discovery (MRD) - allows discovery of multicast routers.

ICMPv6 messages use IPv6 packets for transportation and can include IPv6 extension headers. ICMPv6 includes some of the functionality that in IPv4 was distributed among protocols such as ICMPv4, ARP (Address Resolution Protocol), and IGMP (Internet Group Membership Protocol version 3).

ICMPv6 has simplified the communication process by eliminating obsolete messages.

ICMPv6 messages are subdivided into two classes: error messages and information messages.

Error Messages are divided into four categories:

1. Destination Unreachable
2. Time Exceeded
3. Packet Too Big
4. Parameter Problems

Information messages are divided into three groups:

1. Diagnostic messages
2. Neighbor Discovery messages
3. Messages for the management of multicast groups.

ICMPv6 types and codes

ICMPv6 has a number of messages that are identified by the “Type” field. Some of these types have assigned “Code” fields as well. The table below shows the different types of ICMP Types with their associated codes if there are any.

Type codes 0 − 127 are error messages and type codes 128 − 255 are for information messages.

ICMPv6 Types and Codes

Type Number	Type Name	Code
0	Reserved	0 - no route to destination 1 - communication with destination administratively prohibited 2 - beyond scope of source address 3 - address unreachable 4 - port unreachable 5 - source address failed ingress/egress policy 6 - reject route to destination 7 - Error in Source Routing Header
1	Destination Unreachable
2	Packet Too Big
3	Time Exceeded	0 - hop limit exceeded in transit 1 - fragment reassembly time exceeded
4	Parameter Problem	0 - erroneous header field encountered 1 - unrecognized Next Header type encountered 2 - unrecognized IPv6 option encountered
100	Private Experimentation
101	Private Experimentation
102 - 126	Unassigned
127	Reserved for expansion if ICMPv6 error messages
128	Echo Request
129	Echo Replay
130	Multicast Listener Query
131	Multicast Listener Report
132	Multicast Listener Done
133	Router Solicitation
134	Router Advertisement
135	Neighbor Solicitation
136	Neighbor Advertisement
137	Redirect Message
138	Router Renumbering	0 - Router Renumbering Command 1 - Router Renumbering Result 255 - Sequence Number Reset
139	ICMP Node Information Query	0 - The Data field contains an IPv6 address which is the Subject of this Query. 1 - The Data field contains a name which is the Subject of this Query, or is empty, as in the case of a NOOP. 2 - The Data field contains an IPv4 address which is the Subject of this Query.
140	ICMP Node Information Response	0 - A successful reply. The Reply Data field may or may not be empty. 1 - The Responder refuses to supply the answer. The Reply Data field will be empty. 2 - The Qtype of the Query is unknown to the Responder. The Reply Data field will be empty.
141	Inverse Neighbor Discovery Solicitation Message
142	Inverse Neighbor Discovery Advertisement Message
143	Version 2 Multicast Listener Report
144	Home Agent Address Discovery Request Message
145	Home Agent Address Discovery Reply Message
146	Mobile Prefix Solicitation
147	Mobile Prefix Advertisement
148	Certification Path Solicitation Message
149	Certification Path Advertisement Message
150	ICMP messages utilized by experimental mobility protocols such as Seamoby
151	Multicast Router Advertisement
152	Multicast Router Solicitation
153	Multicast Router Termination
154	FMIPv6 Messages
155	RPL Control Message
156	ILNPv6 Locator Update Message
157	Duplicate Address Request
158	Duplicate Address Confirmation
159 − 199	Unassigned
200	Private experimentation
201	Private experimentation
255	Reserved for expansion of ICMPv6 informational messages

IP

Internet Protocol (IP) is the primary part of the Network Layer of the OSI Model that is responsible for routing traffic across network boundaries. It is the protocol that is responsible for addressing. IPv4 is probable the version that most people are familiar with and it has been around since 1974. IPv6 is its current successor and due to a shortage of available IPv4 addresses compared to the explosive increase in the number of devices that use IP addresses, IPv6 is rapidly increasing in use.

When IP is chosen as the protocol type the available option to further specify the protocol is the protocol number. This is used to narrow down which protocol within the Internet Protocol Suite and provide a more granular control.

Protocol number

IP is responsible for more than the address that it is most commonly associated with and there are a number of associated protocols that make up the Network Layer. While there are not 256 of them, the field that identifies them is a numeric value between 0 and 256.

In the Internet Protocol version 4 (IPv4) [RFC791] there is a field called “Protocol” to identify the next level protocol. This is an 8 bit field. In Internet Protocol version 6 (IPv6) [RFC2460], this field is called the “Next Header” field.

Protocol Numbers

#	Protocol	Protocol's Full Name
0	HOPOPT	IPv6 Hop-by-Hop Option
1	ICMP	Internet Control Message Protocol
2	IGMP	Internet Group Management
3	GGP	Gateway-to-Gateway
4	IPv4	IPv4 encapsulation Protocol
5	ST	Stream
6	TCP	Transmission Control Protocol
7	CBT	CBT
8	EGP	Exterior Gateway Protocol
9	IGP	Any private interior gateway (used by Cisco for their IGRP)
10	BBN-RCC-MON	BBN RCC Monitoring
11	NVP-II	Network Voice Protocol
12	PUP	PUP
13	ARGUS	ARGUS
14	EMCON	EMCON
15	XNET	Cross Net Debugger
16	CHAOS	Chaos
17	UDP	User Datagram Protocol
18	MUX	Multiplexing
19	DCN-MEAS	DCN Measurement Subsystems
20	HMP	Host Monitoring
21	PRM	Packet Radio Measurement
22	XNS-IDP	XEROX NS IDP
23	TRUNK-1	Trunk-1
24	TRUNK-2	Trunk-2
25	LEAF-1	Leaf-1
26	LEAF-2	Leaf-2
27	RDP	Reliable Data Protocol
28	IRTP	Internet Reliable Transaction
29	ISO-TP4	ISO Transport Protocol Class 4
30	NETBLT	Bulk Data Transfer Protocol
31	MFE-NSP	MFE Network Services Protocol
32	MERIT-INP	MERIT Internodal Protocol
33	DCCP	Datagram Congestion Control Protocol
34	3PC	Third Party Connect Protocol
35	IDPR	Inter-Domain Policy Routing Protocol
36	XTP	XTP
37	DDP	Datagram Delivery Protocol
38	IDPR-CMTP	IDPR Control Message Transport Proto
39	TP++	TP++ Transport Protocol
40	IL	IL Transport Protocol
41	IPv6	IPv6 encapsulation
42	IPv6	SDRPSource Demand Routing Protocol
43	IPv6-Route	Routing Header for IPv6
44	IPv6-Frag	Fragment Header for IPv6
45	IDRP	Inter-Domain Routing Protocol
46	RSVP	Reservation Protocol
47	GRE	General Routing Encapsulation
48	DSR	Dynamic Source Routing Protocol
49	BNA	BNA
50	ESP	Encap Security Payload
51	AH	Authentication Header
52	I-NLSP	Integrated Net Layer Security TUBA
53	SWIPE	IP with Encryption
54	NARP	NBMA Address Resolution Protocol
55	MOBILE	IP Mobility
56	TLSP	Transport Layer Security Protocol using Kryptonet key management
57	SKIP	SKIP
58	IPv6-ICMP	ICMP for IPv6
59	IPv6-NoNxt	No Next Header for IPv6
60	IPv6-Opts	Destination Options for IPv6
61		any host internal protocol
62	CFTP	CFTP
63		any local network
64	SAT-EXPAK	SATNET and Backroom EXPAK
65	KRYPTOLAN	Kryptolan
66	RVD	MIT Remote Virtual Disk Protocol
67	IPPC	Internet Pluribus Packet Core
68		any distributed file system
69	SAT-MON	SATNET Monitoring
70	VISA	VISA Protocol
71	IPCV	Internet Packet Core Utility
72	CPNX	Computer Protocol Network Executive
73	CPHB	Computer Protocol Heart Beat
74	WSN	Wang Span Network
75	PVP	Packet Video Protocol
76	BR-SAT-MON	Backroom SATNET Monitoring
77	SUN-ND	SUN ND PROTOCOL-Temporary
78	WB-MON	WIDEBAND Monitoring
79	WB-EXPAK	WIDEBAND EXPAK
80	ISO-IP	ISO Internet Protocol
81	VMTP	VMTP
82	SECURE-VMTP	SECURE-VMTP
83	VINES	VINES
84	TTP	TTP
84	IPTM	Protocol Internet Protocol Traffic
85	NSFNET-IGP	NSFNET-IGP
86	DGP	Dissimilar Gateway Protocol
87	TCF	TCF
88	EIGRP	EIGRP
89	OSPFIGP	OSPFIGP
90	Sprite-RPC	Sprite RPC Protocol
91	LARP	Locus Address Resolution Protocol
92	MTP	Multicast Transport Protocol
93	AX.25	AX.25 Frames
94	IPIP	IP-within-IP Encapsulation Protocol
95	MICP	Mobile Internetworking Control Pro.
96	SCC-SP	Semaphore Communications Sec. Pro.
97	ETHERIP	Ethernet-within-IP Encapsulation
98	ENCAP	Encapsulation Header
99		any private encryption scheme
100	GMTP	GMTP
101	IFMP	Ipsilon Flow Management Protocol
102	PNNI	PNNI over IP
103	PIM	Protocol Independent Multicast
104	ARIS	ARIS
105	SCPS	SCPS
106	QNX	QNX
107	A/N	Active Networks
108	IPComp	IP Payload Compression Protocol
109	SNP	Sitara Networks Protocol
110	Compaq-Peer	Compaq Peer Protocol
111	IPX-in-IP	IPX in IP
112	VRRP	Virtual Router Redundancy Protocol
113	PGM	PGM Reliable Transport Protocol
114		any 0-hop protocol
115	L2TP	Layer Two Tunneling Protocol
116	DDX	D-II Data Exchange (DDX)
117	IATP	Interactive Agent Transfer Protocol
118	STP	Schedule Transfer Protocol
119	SRP	SpectraLink Radio Protocol
120	UTI	UTI
121	SMP	Simple Message Protocol
122	SM	SM
123	PTP	Performance Transparency Protocol
124	ISIS over IPv4
125	FIRE
126	CRTP	Combat Radio Transport Protocol
127	CRUDP	Combat Radio User Datagram
128	SSCOPMCE
129	IPLT
130	SPS	Secure Packet Shield
131	PIPE	Private IP Encapsulation within IP
132	SCTP	Stream Control Transmission Protocol
133	FC	Fibre Channel
134	RSVP-E2E-IGNORE
135	Mobility Header
136	UDPLite
137	MPLS-in-IP
138	manet
139	HIP
140	Shim6
141	WESP
142	ROHC
143 − 252	Unassigned	Unassigned
253		Use for experimentation and testing
254		Use for experimentation and testing
255	Reserved

Further information can be found by researching RFC 5237.

Service groups

Just like some of the other firewall components, services can also be bundled into groups for ease of administration.

Creating a service group

1. Go to Policy & Objects > Objects > Services.
2. Select the down arrow next to Create New, select Service Group.
3. Input a Group Name for the list of services.
4. Input any additional information in the Comments field.
5. Choose a Type; either Firewall or Explicit Proxy.
6. Next to Members there is a dropdown menu that can be used to select from the available Services. It is possible to select more than 1 entry. Just select the green plus sign next to the field to add an additional entry. Select the “X” icon in the field to remove an entry.
7. Press OK.

Example scenario: Supporting audio/visual conferencing

The feature, and the transmitting of data for the purpose of, Tele-conferencing or Audio/Visual Conferencing is covered by a number of standards: •  The IETF standard known as the Binary Floor Control Protocol (BFCP). •  RFC 4582, for SIP-based video devices •  The ITU standard H.239 (for H.323-based video devices) While these standards have been set up by various authoritative bodies and can take place on different layers of the OSI model, they share common requirements that are addressed by the FortiGate firewall’s ability to manage the traffic and the protocols involved. This means that the same ability that make the device RFC 4582 compliant makes it compliant with H.239 as well.

To demonstrate how services and service groups are used we show the setup of a firewall that will need to support the connectivity of a video conferencing unit. The FortiGate does not manipulate or change the content of the traffic but it does allow for the traffic to pass through the device. In this case it allow for only the needed traffic to pass through the device so as to allow the functionality of Audio Visual Conference call but not to allow other traffic through.

The theoretical location for this scenario is a hospital that hosts conferences and lectures from doctors from all over the world, sometimes from multiple locations, using video conferencing technology such as a Polycom Video Conference system. There is a special room set up with dedicated Ethernet connectivity to the Internet. A hospital has a lot of sensitive information going over its network so the setup has to be secure to prevent any chance of penetration.

The approach is fairly simple. The conference room has a dedicated port on the FortiGate (port #7) and its own LAN. We will assume that the interface has already been configured properly. Video conference traffic can come from the Internet to the Polycom in that room and traffic can get out to the Internet, but traffic going to other areas of the hospital network have to go through the FortiGate and traffic going from the Video Conference LAN is thoroughly filtered.

To give an idea of how extensive this can be, we will use an extreme case and include just about all of the services that could be commonly used in one of these setups. The protocols listed here may differ from other setups. It will depend on which features are being used and which equipment is within the network. Always check the documentation that comes with the set up before opening ports into your network.

VIP

In this particular case there is an IP address set aside for the conferencing system so a separate VIP is not needed for every port. One Virtual IP will be created for the system and then only the approved of protocols will be allows through the firewall.

Name	Vid-Conf_Room216
External Interface	wan1
External IP Address/Range	256.87.212.51 – 256.87.212.51
Mapped IP Address/Range	192.168.7.25 – 192.168.7.25
Port Forwarding	not selected

Creating an address for the subnet

In the same way that the VIP was created to identify and direct incoming traffic an address should be created to identify the addresses of computer that will be in the Conference room. This included computers on the LAN as well as the Teleconferencing equipment.

1. Go to Policy & Objects > Objects > Addresses.
2. Select Create New.
3. Fill out the fields with the following information:

Category	Address
Name	Port7_subnet
Type	Subnet
Subnet/IP Range	192.168.7.0/255.255.255.0
Interface	port7
Show in address list	checked

Configuring the services

Services already created:

The following are standard services that have already been created by default:

HTTP	TCP 80
SNMP	TCP 161-162/UDP 161-162
LDAP	TCP 389
HTTPS	TCP 443
SYSLOG	UDP 514

Existing services to be edited:

There are a few services that have already been created for you, but they need to be expanded to accommodate the list of protocols listed for this scenario.

The default h323 contains:

• TCP 1503
• UDP 1719
• TCP 1720

We need to add:

• TCP1719

The default SIP contains:

• UDP 5060

We need to add:

• TCP 5060

H323 service

1. Go to Policy & Objects > Objects > Services.
2. Scroll down to the section: VoIP, Messaging & Other Applications.
3. Select H323.
4. Select Edit.
5. In the Protocol section add the additional protocol:

Protocol Type	TCP
Destination port /Low	1719

6. Select OK to save.

SIP service

1. Go to Policy & Objects > Objects > Services.
2. Scroll down to the section: VoIP, Messaging & Other Applications.
3. Select SIP.
4. Select Edit.
5. In the Protocol section add the additional protocol:

Protocol Type	TCP
Destination port /Low	5060

6. Select OK to save.

Custom services that need to be created

There are a number of possible services that may need to be added from scratch rather than editing existing ones. While it is possible to create a single custom service that contains all of the open ports needed, it make more sense to make this modular in case only a small subset of the service needs to be added to another policy.

Polycom API

1. Go to Policy & Objects > Objects > Services.
2. Select Create New.
3. Fill in the fields of the new service with the following information:

Name	Polycom API
Service Type	Firewall
Category	VoIP, Messaging & Other
Protocol Type	TCP/UDP/SCTP
Protocol	TCP/UDP/SCTP
Protocol	TCP
Destination Port - Low:	24
Destination Port - High:	<leave blank>

4. Select OK.

Polycom endpoints

1. Go to Policy & Objects > Objects > Services.
2. Select Create New.
3. Fill in the fields of the new service with the following information:

Name	Polycom Endpoints
Service Type	Firewall
Category	VoIP, Messaging & Other
Protocol Type	TCP/UDP/SCTP
Protocol	TCP
Destination - Low:	3230
Destination - High:	3253

4. Select OK.

Other Services to add in the same way:

Name of Service	Category	Protocol & Port #
LDAP secure communications	Authentication	TCP 636
Win 2000 ILS Registration	Network Services	TCP 1002
Gatekeeper discovery	VoIP, Messaging & Other Applications	TCP 1718
Audio Call Control	VoIP, Messaging & Other Applications	TCP 1731
Polycom proprietary Global directory data	VoIP, Messaging & Other Applications	TCP 3601
Polycom People+Content	VoIP, Messaging & Other Applications	TCP 5001
HTTP Server Push	Web Access

Creating the service group

1. Go to Firewall Objects > Service > Groups.
2. Select Create New.
3. Build the Service group by filing in the fields with the following information

Group Name	A-V_Conference
Type	Firewall
Members (click in the drop down menu to add the following services)	•  HTTP •  SNMP •  LDAP •  HTTPS •  SYSLOG •  Polycom API •  Polycom Endpoints •  LDAP secure communications •  Win 2000 ILS Registration •  Gatekeeper discovery •  Audio Call Control •  Polycom proprietary Global directory data •  Polycom People+Content •  HTTP Server Push

Creating the IPS security profile

This is by no means the only way to set up this IPS filter, but it is the way that the fictional System Administrator wants it set up. Yours may be different.

1. Go to Security Profiles > Intrusion Protection > IPS Sensors.
2. Create a new sensor.

Name	A-V_Conference-incoming

3. Select OK.
4. In the newly created sensor, create a new IPS filter.

Sensor Type	Filter Based
Filter Options	Advanced
Severity	•  Critical •  High •  Medium •  Low
Target	Server
OS	Windows
Application	•  IIS •  other
Protocol Use the [Show more...] option	•  HTTP •  LDAP •  SIP •  SSL •  H323
Packet logging	enabled

Based on these filters there should be somewhere in the neighborhood of 750 signatures that the FortiGate will run traffic against in the IPS engine.

Policies

Incoming policy

A policy has to be made to allow the traffic to come in from the Internet to connect to the Tele-conferencing server equipment.

1. Go to Policy & Objects > Policy > IPv4.
2. Select Create New.
3. Fill out the fields with the following information:

Policy Type	Firewall
Policy Subtype	Address
Incoming Interface	wan1
Source Address	all
Outgoing Interface	port7
Destination Address	Vid-Conf_Room216
Schedule	always
Service	A-V_Conference
Action	ACCEPT
Enable NAT	<not enabled>
Logging Options	Logging is a good idea but how much will depend on storage capabilities.
Security Profiles	Turn on IPS and choose “A-V_Conference-incoming”
Traffic Shaping, Web cache, WAN Optimization, Disclaimer:	The use of these features will depend on your network environment and should be decided by the network architect, as the decision will largely be based on network bandwidth, usage and importance of Video conferencing compared to other traffic.

4. Select OK.

The policy will then need to be put in the correct position in the sequence of the policies. Because it is a rather focused policy it should be acceptable to place it near the top of the policy order sequence.

Outgoing policy

A policy has to be made to allow the traffic to leave from the subnet in the conference room to the Internet, not only for the traffic for the Tele-conferencing equipment but for normal traffic of users on the Internet such as web research and email. The traffic is outgoing so there is less of a need for an Intrusion Protection System filter, but check with the network architect in case there is a need for using one of the other security profiles.

1. Go to Policy & Objects > Policy > IPv4.
2. Select Create New.
3. Fill out the fields with the following information:

Policy Type	Firewall
Policy Subtype	Address
Incoming Interface	port7
Source Address	Port7_subnet
Outgoing Interface	wan1
Destination Address	all
Schedule	always
Service	any
Action	ACCEPT
Enable NAT	enabled Use Destination Interface Address
Logging Options	Logging is a good idea but how much will depend on storage capabilities.
Security Profiles	<see above>
Traffic Shaping, Web cache, WAN Optimization, Disclaimer:	The use of these features will depend on your network environment and should be decided by the network architect, as the decision will largely be based on network bandwidth, usage and importance of Video conferencing compared to other traffic.

4. Select OK.

The policy will then need to be put in the correct position in the sequence of the policies.