[asterisk-users] Losing local SIP phones when internet goes down?

[Mark Hulber]

I have the same problem.  I have asterisk on the public internet and 
other ips on the private lan.  When the internet goes down my private 
asterisk network is compromised.  My thought is that it has something to 
do with the ports/ips on which asterisk is trying to communicate.  It 
may be a configuration issue but as of yet I haven't figured it out.

On 2/4/2010 9:05 PM, Nikhil Nair wrote:
> Hi,
>
> I'm getting some strange behaviour on Asterisk 1.4 running on Debian
> Stable (Lenny).  I suspect it's something to do with my setup, rather than
> a bug, but I'm struggling to see it, and would appreciate any input.
>
> Setup: PC with two ethernet cards: eth0 goes to local network, including
> two SIP phones (Aastra 9112i, wired, and Nokia E75, over WIFI); eth1 goes
> to router and thence to the internet over ADSL.  PC also has one Zap
> channel.
>
> the SIP phones use DHCP but have defined IP addresses (DHCP server running
> on the PC).  The PC is also running a firewall (FIAIF), but not a DNS
> server.
>
> Version of Debian Asterisk package: 1:1.4.21.2~dfsg-3+lenny1
>
> Problem: When the internet connection goes down (which has been happening
> sporadically of late), connections to the two SIP phones on the local
> network get lost; ongoing calls from one of these phones over the Zap
> channel may get terminated, despite not using the internet.
>
> I can reproduce this by switching off my ADSL router; however, if I simply
> take down the eth1 interface completely (by using "ifdown eth1", which
> executes "route del default gw ... eth1" and "ifconfig eth1 down"), the
> connections to the two SIP phones continue with no problems at all.
>
> I enclose an extract from my sip.conf below.  Also, the logs indicate that
> Asterisk thinks the SIP phones are no longer reachable (ping timing out),
> while a manual ping from the same machine shows no trouble at all: the
> wired phone is responding in less than 2 ms each time, while the wireless
> one was a max of about 120 ms.
>
> Any thoughts much appreciated!  Hopefully it's something obvious that I've
> overlooked...
>
> Oh, BTW, the local phones are on a private net (10.9.8.xxx), but as it's
> the Asterisk box that's doing the NAT'ing, I used nat=no; I presume that's
> correct.  eth0 has address 10.9.8.1, while eth1 has a global internet IP
> address.
>
> Cheers,
>
> Nikhil.
>
> -----
>
> Extract from sip.conf:
>
> [general]
> context=incoming
> srvlookup=yes
> realm=nikhil-nair.net
> ; Various "register=>" statements, not relevant to the local phones
>
> [101] ; Aastra 9112i at 10.9.8.101
> type=friend
> secret=...
> qualify=yes ; Qualify peer is no more than 2000 ms away
> nat=no ; This phone is not natted
> host=dynamic ; This device registers with us
> canreinvite=no ; Asterisk by default tries to redirect
> context=local
> disallow=all
> allow=alaw
> allow=ulaw
>
> [111] ; Nokia E75 via WIFI access point, at 10.9.8.111
> type=friend
> secret=...
> qualify=yes ; Qualify peer is no more than 2000 ms away
> nat=no ; This phone is not natted
> host=dynamic ; This device registers with us
> canreinvite=no ; Asterisk by default tries to redirect
> context=local
> disallow=all
> allow=alaw
> allow=ulaw
> allow=gsm
>
>