[Asterisk-Users] SIP qualify question.

[Ray Van Dolson]

When qualify is set to yes in sip.conf for a "friend" and the OPTIONS packet
gets returned with an ICMP port unreachable message, what is the behavior of
Asterisk?

It looks to me like Asterisk tries sending the OPTION request again right away
(well within a second or two).

Some of our devices are being Linux firewalls that make use of iptables to do
portforwarding.  This generates entries in /proc/net/ip_contrack.  From time
to time, these entries get out of whack or a connection gets stale and inbound
requests start getting rejected with port unreachable messages.

In order to get things working again, I need to expire the corresponding entry
in ip_conntrack (I have my timeouts set low -- to 15 seconds).  The problem is
is that Asterisk is sendint the qualify requests so quickly that the timer
keeps resetting on my ip_conntrack entry and never expires.  I have to either
reboot the Linux device to clear the entry manually or block requests from
Asterisk for 15 seconds.  Then things work fine again.

Wondering if there's a good way to make Asterisk back off a little if a SIP
OPTIONS request as part of qualify doesn't get through.  I suppose modifying
the source code is our best bet.

Setting qualify to a milliseconds value doesn't appear to affect these
retransmits btw.

Thanks!