General SIP setup guide for 7800 series 

Generally, there are two types of VoIP setup behind routers

a)      Connecting VoIP SIP phone(s) behind the 7800 series router without any internal SIP server or PBX. In another words, you only have SIP phone(s)/ ATA(s) on your LAN.

b)      A local PBX or SIP server is located on your local network alongside IP phone(s). i.e. you have both server and phone(s) on your LAN.

What you will need from your SIP/ VoIP provider:

1)      SIP register port – UDP 5060 is the common port but some provide might use a range e.g. UDP 5060-5082.

2)      RTP ports – theses ports are used for audio so pretty important for voice over IP. The SIP register port allows you to register with the SIP server but RTP ports are the one handling the audio. Even if your device(s) is shown as registered but without these RTP ports working you are not going to have any audio. RTP ports are usually in range, e.g. UDP 10000-20000. You will need to find out from your provider what ports they use for their particular server.

3)      Please check with your provider if they have their own STUN server, if so please ask them to provide their STUN server address or IP address. Usually STUN server users UDP 3478. A lot of SIP phone(s) or devices already supports STUN server with option to enable STUN server on their web interface.

STUN server is used to resolve issues caused by NAT e.g. one way audio issue is very common and can usually be resolved by using STUN server.

Further details on STUN can be found from http://www.voip-info.org/wiki/view/STUN

Always DISABLE the SIP ALG from the router’s web interface first.

You need disable SIP ALG under Advance > Configuration > Virtual Server > ALG

Scenario (a) IP phone(s) / ATA(s) only on LAN

Probably the most common setup, a SIP/ VoIP account is obtain from a provider and you are using IP phone(s), ATA adapter(s) or softphone from your computer(s).

1)      Connect the device(s) to the router via Ethernet or wireless as usual.

2)      You do not need to set up DMZ or port forwarding /Virtual server.

3)      You will need to setup packet filter rules to let the SIP/ VoIP traffic from the Internet to come in through the firewall.

4)      On the router’s web interface, please click on Advanced > Configuration > Firewall > Packet filter.

5)      You will need to add server rules in according to the information from your SIP/ VoIP provider. e.g. SIP register port(s), RTP port(s) and STUN server port. If your provider do not have their own STUN server, you can always use some public STUN server e.g. stun.xten.com on your SIP devices web interface. Please note that STUN has to be configured on your SIP device(s) and not the router. We are only setting up the router to let the right traffic through the firewall. Please refer to the screen shot below for packet filter rules. The rules are just typical examples and might be different from your provider’s.

            Once the rules are created, please save the config by pressing “Save Config” and then restart the router.

Scenario (b) PBX/ SIP server with IP phone(s)/ SIP device(s) also on LAN

This setup is less common and setup is slightly different now that we have a PBX/ SIP server on the LAN as well.

1)      Since the local PBX/ SIP server will be handling all the SIP/ VoIP device(s) effectively we only have one device talking to the Sip provider’s server. So we only need to setup relevant rules for the SIP/ PBX server.

2)      You will need to setup port forwarding/ Virtual server instead of packet filter this time. The 7800 series router should automatically let the traffic through its firewall once a virtual server/ port forwarding rule is in place.

3)       You can setup Virtual server by going on the router’s web interface: Advanced > Configuration > Virtual Server > Port Mapping.

4)      Please refer to the screen shot below and again the screen shot only uses typical examples and might be different from your provider’s.

Again once you have added the Virtual server rules then save the config by clicking “Save Config” and then restart the router.