SIP ALG is used to try and avoid configuring Static NAT on a router. Its implementation, however, varies from one router to another, often making it difficult to inter-operate a router with SIP ALG enabled with a PBX. In general, you would want to disable SIP ALG and configure one to one port mapping on the router.
In this article, we will show you how to disable SIP ALG on a Netgear router. SIP ALG on this router is known to cause problems with VoIP calls.
Follow this step-by-step guide:
- Open the Netgear router’s configuration by browsing to its LAN Address (http://192.168.0.1 by default).
- Log on to the router’s configuration. The default username is ‘admin’ and the default password is ‘password’
- In the main menu, select Advanced and then WAN Setup
- Enable the option Disable SIP ALG
- Click Apply to apply this setting.
- The SIP phones behind this router should be configured not to use STUN.