A number of additional ports have been opened on Kamailio – the relevant one here is TCP 443. An INVITE comes in from a UA whose from URI is suffixed with :443. PUA generates a PUBLISH out of this. Log is at https://gist.githubusercontent.com/phil-lavin/c381d556c22fd29b4fde/raw/77c5b5083573fe7ef04b5e196d3f320bda6b56c2/gistfile1.txt.

The relevant bit to the issue is the last line. PUA is trying to send the PUBLISH to the address and port taken from the from URI… however it sends it over UDP. Because Kamailio is not bound to UDP 443, the PUBLISH is not received.

A hacky “fix” is to make Kamailio bind to UDP 443 as well as TCP 443. I will dig into this deeper on Monday in an attempt to find a better fix.

Suggestions around what is the best solution would be appreciated. I’m thinking that sending this over TCP is not desirable in most instances – unless perhaps Kamailio is only bound to TCP ports?

Cheers