I am testing to get asterisk listen on 2 ports using port forwarding as per below.
iptables -t nat -A PREROUTING -i em1 -p udp --dport 5062 -j REDIRECT --to-ports 5060
Asterisk is on Public IP and nat is off. Test scenarios
Changed sip client to use 5062 and I could able to connect to the asterisk server and make calls but around 30 to 32seconds, it gets disconnected with below message**(happens only on particular mobile operator connection)**
_WARNING chan_sip.c: Retransmission timeout reached on transmission 304768-c01a8c0-13c4-45026-4f02-29dd718-4f02 for seqno 2 (Critical Response)
With the exact same set up but switched the client to different operator’s data connection or wifi connection, there is no issue at all on 5060 or 5062.
That particular mobile operator blocks 5060 and I am assuming they might have blocked other ports that affecting the proper sip/rtp messages ?
Kindly advise what could possibly be the problem.