I've discovered a bug with multicast paging that affects phones (like Cisco/Linksys/Sipura) that listen for multicast session control packets to hang up. Sniffing on the FreeSWITCH shows that FreeSWITCH does not respond to caller BYE on hangup, but waits five minutes before timing out waiting for media. It then sends its own BYE and sends multicast session control packets. For those five minutes, mod_efs is stuck continuing in a for(;;) loop and phones that count on hearing the multicast session control packets stay in session. The problem is with FreeSWITCH not replying to client BYE. I don't think the problem is necessarily in mod_esf, but currently this is beyond my ability to troubleshoot further. If anyone has an intuition on how to proceed, please let me know. I've raised a bug report in JIRA and it's been auto-assigned, but I haven't seen an indication it's been acknowledged. The bug is here: http://jira.freeswitch.org/browse/FS-4067 I've attached pcap and logs to the bug report.