Bug#491428: Asterisk don't recive SIP request while communication with DNS

[Robert Paciorek]

Package: asterisk
Version: 1:1.4.21.1~dfsg-1
Severity: important


Hi,

When Asterisk have open connection to DNS serwer (in ESTABLISHED state) he 
don't recive incoming SIP request (sending request neither to be show in "sip 
debug"), though he have open 5060 udp port.

This is problematic for example when Asterisk have register directive in 
sip.conf (to oudside SIP serwer) and ISP is down, becouse preclude register 
internal sip phone in Asterisk ("registration failed: 408 Request Timeout").

In older asterisk version problem exist too.

Problem can be simulated via drop DNS reply in iptables:
	iptables -I INPUT -p udp --sport 53 -j DROP
on asterisk server.


Thanks,
Robert Paciorek
http://www.opcode.eu.org/bercik