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!