Disable SIP ALG on Tomato Shibby

Mark Berry March 16, 2017

A PBX vendor like 3CX may tell you to disable SIP ALG on your router.

I’m running Tomato on my router, specifically Tomato Firmware 1.28.0000 MIPSR2-132 K26 Max. With the help of this thread, I checked and disabled SIP ALG.

Under Advanced > Conntrack/Netfilter, in the Tracking/NAT Helpers section, if SIP is checked, SIP ALG is enabled:

tomato sip alg 1

You can confirm this from Tools > System Commands by running lsmod. If you see nf_conntrack_sip or nf_nat_sip, SIP ALG is enabled:

tomato sip alg 2

Uncheck SIP:

tomato sip alg 3

And the _sip modules go away:

tomato sip alg 4

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