Summary:ASTERISK-11225: Asterisk stops responding to sip traffic if DNS doesn't respond during SIP registration
Reporter:Matthew Stapleton (staples1347)Labels:
Date Opened:2008-01-13 00:33:12.000-0600Date Closed:2011-06-07 14:08:14
Versions:Frequency of
Description:If the internet gateway goes down or the DNS server stops responding, then during SIP registration to a VoIP provider, Asterisk will stop responding to all SIP packets even if they are from other SIP devices such as internal phones.

To test this either shutdown the internet gateway machine, or block DNS request packets from the Asterisk machine and wait for the next SIP registration.  Another way to test is set resolv.conf on the Asterisk machine to use an invalid IP address for the DNS server, and then restart Asterisk.

Blocking outgoing DNS directly on the Asterisk machine with iptables or responding to the DNS request with icmp-host-unreachable 'causes a timeout to the VoIP provider but doesn't stop other SIP traffic.


The Asterisk machine was running Asterisk 1.2.14 on AMD64 Gentoo Linux with kernel: 2.6.18-gentoo-r6 so I upgraded to Asterisk and it still had the problem.
Comments:By: Michiel van Baak (mvanbaak) 2008-01-13 05:37:53.000-0600

1.2 is in security maintenance only mode.
Can you confirm this one with the latest 1.4 code ?

By: Joshua C. Colp (jcolp) 2008-01-14 08:10:32.000-0600

This is an issue that is already well known. The DNS resolver that we use is blocking, which means if the DNS server is down or slow it will take some time for it to return and thus block other things. There is nothing we can do in 1.4 to fix this, but hopefully we'll figure something out for 1.6.