i was wondering why sometimes requests to rtpengine don't get through and icmp unreachable destination error message is received. it turned out that in these error cases ip packet containing the rtpengine request has 0x02 (don't fragment) flag set even when the packet was bigger than 4 KB. in this case kamailio was running in an amazon container which may be doing something weird.

is it somehow possible from the application (= kamailio) to control setting of that flag?

-- juha