[asterisk-users] Multiple SIP phones behind a Linksys firewall

[Philip Prindeville]

Luki wrote:
>> I always assumed that you can have multiple SIP phones behind a Linksys
>> firewall/router (WRT54G) all using the same STUN server/port.
>>     
>
> I got 10-20 SPA942's behind a OpenWRT router (on WRT54G, WRTSL54GS,
> ...) at several sites, no STUN, no special configuration, no problems
> at all. Just as a precaution, I set the SIP port and RTP port range
> for each phone differently so that it's unique (i.e. Phone 1 SIP port
> 6001 and RTP 10100-10199, etc.) but that's really just a precaution to
> help the the Linux' conntrack on the OpenWRT a bit. It's not really
> needed as the router will resolve port conflicts by rewriting the
> ports transparently.
>
> Bottom line, a few phones behind a well-behaved NAT should work just fine.
>
> /Luki
>   

What do the iptables look like on OpenWRT?  Are they configured as part 
of the release, or left to the user to configure, or what?

I'm using a Soekris net5501 running Astlinux 0.5 trunk (with a patched 
version of Arno's firewall script that has not yet been integrated into 
the source tree): it supports the ip_conntrack_sip and ip_nat_sip modules.

I have the firewall/Asterisk running on this box at the "home office", 
with a couple of SPA's behind it (942's and a PAP2-NA).

Then I have remote offices also with SPA-942's sitting behind a 
similarly configured Soekris 942 (only difference being that Asterisk 
isn't running on it).

I had all of the usual NAT related issues (one-way audio, no audio, etc) 
until I patched in the NAT SIP modules.

I've attached it.  This works with arno-iptables-firewall-1.8.8l.

Arno says he's working on a plug-in for 1.8.8m and 1.9.0? that will be 
released separately, but I've haven't yet seen it.

-Philip

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