Chapter 22 VoIP Solutions: SIP : FortiGate VoIP solutions: SIP : How the SIP ALG performs NAT : SIP NAT configuration example: destination address translation (destination NAT) : Configuration steps - web‑based manager
  
Configuration steps - web‑based manager
To add the SIP proxy server firewall virtual IP
1. Go to Policy & Objects > Objects > Virtual IP and select Create New.
2. Add the SIP proxy server virtual IP.
VIP Type
IPv4 VIP
Name
SIP_Proxy_VIP
Interface
port1
Type
Static NAT
External IP Address/Range
172.20.120.50
Mapped IP Address/Range
10.31.101.50
To add a firewall address for the SIP proxy server
1. Go to Firewall Objects > Address > Addresses.
2 Add the following for the SIP proxy server:
VIP Type
IPv4 VIP
Name
SIP_Proxy_Server
Type
Subnet
Subnet / IP Range
10.31.101.50/255.255.255.255
Interface
port2
To add the security policies
1. Go to Policy & Objects > Policy > IPv4.
2. Add a destination NAT security policy that includes the SIP proxy server virtual IP that allows Phone B (and other SIP phones on the Internet) to send SIP request messages to the SIP proxy server.
Incoming Interface
port1
Source Address
all
Outgoing Interface
port2
Destination Address
SIP_Proxy_VIP
Schedule
always
Service
SIP
Action
ACCEPT
3. Select Enable NAT and select Use Destination Interface Address.
4. Under UTM Security Profiles, select Use Standard UTM Profiles.
5. Turn on VoIP and select the default VoIP profile.
6. Select OK.
7. Add a source NAT security policy to allow the SIP proxy server to send SIP request messages to Phone B and the Internet:
Incoming Interface
port2
Source Address
SIP_Proxy_Server
Outgoing Interface
port1
Destination Address
all
Schedule
always
Service
SIP
Action
ACCEPT
8. Select Enable NAT and select Use Destination Interface Address.
9. Turn on VoIP and select the default VoIP profile.
10. Select OK.