TomatoUSB

I've been trying to get my RT-N16 optimized for VOIP and have seen conflicting suggestions for how to handle the conntrack / netfilter settings, as well as the SIP helper.

It seems like setting UDP Timeout to Unreplied: 10 / Assured: 300 seems to be the recommended values, but how about the SIP Helper? Should that be on or off?

From my experience, I leave the default settings on the Tomatousb, and it works just fine, UDP timeout at 30, and Sip helper to be left on. I have no issues with them on for my voip service. Im running also a RT-N16 with TomatoUSB VPN and PAP2T-NA. If you experience any issues, turn the off and see if it helps.

Cheers

Take a fools advice — turn off SIP helper, at least in the current stable builds off the main TomatoUSB website.

It is possible that some of the more recent RAF, etc. builds may include newer versions of Conntrack, etc. but the early version DEFINITELY causes problems in certain cases.

Specifically, if you are using PhonePower's SIP Trunking option with an Asterisk server, then SIP helper will corrupt the destination of inbound RTP audio packets destined for Asterisk. The end result is that you get no inbound audio on incoming or outgoing calls. It passes all the way through the router, through the firewall on my Asterisk server, and then gets basically chucked as an invalid. If I turn off SIP helper, everything works just fine.

With some of my other trunks (SIPStation for one), SIP helper hasn't caused me any problems that I am aware of — but it hasn't helped in any way I can tell either (i.e. it works just as well with it turned off).

Just FYI - there have been some changes which relate to the SIP helper, I believe, but whether or not they will help I don't know. Just don't stop trying it, because one day, it might be fine :-)

I need to retest my own configuration with some of the newer builds — but the last, year old, stable releases off the main website DEFINITELY have issues in the SIP helper module.

Unfortunately, the last time I tried some of the newer builds (specifically RAF) I ran into some weird routing problems related to a nailed Static Key OpenVPN link — which is a major headache as that is how our buildings (and our phone system) are tied together.

Oh wow! This thread helped to solve a nagging problem on Tomato for me! My SIP device, called a "Biscotti" would drop calls after about 15 seconds on the latest Toastman build (1.28.0503) - but it would work fine with DDWRT on the same router. I had tried everything I could think of - to no avail. When I turned OFF the SIP NAT helper - problem solved!!! So I guess there might still be bugs with SIP helper… Long live TomatoUSB!!!

Glad you got things going.
For those interested, Victek has added siproxd in some of his firmware (tomatoraf), and could also be worthy of looking into if you're having problems.

Great !

If it helps anyone then i have two SIP devices. A D-link PAP2 and Vonage VTA connected behind a WRT54-TM running Shibby Mod ND-115. Even had K26-two digit versions before and never encountered any issues. If i recall correctly, i had Vonage VTA connected to R-16 for a while running Shibby K26 114 and didnt encounter any problem either. I have ordered a Linksys E3000 for some firmware development testing and i definitely will look into this issue when i start building.

Have a great day!