I actually had this exact problem, and because I knew when I was first hop and when not, I ended up adding if conditions to solve the problem. I would love to know the answer to this too and the correct reason as to why it happens and how to correct it. On Wed, Oct 3, 2018 at 11:34 PM Sergiu Pojoga &lt;pojogas(a)gmail.com <mailto:pojogas@gmail.com>> wrote: Hi ppl, If I add a FQDN advertise address to the listen statement, /is_first_hop() <https://kamailio.org/docs/modules/4.3.x/modules/siputils.html#siputils.f.is_first_hop>/ seems to return FALSE no matter how I play with the listen and alias settings. listen=udp:1.1.1.1:5060 <http://1.1.1.1:5060> advertise sip.mydomain.net:5060 <http://sip.mydomain.net:5060> alias="sip.mydomain.net:5060 <http://sip.mydomain.net:5060>" This statement doesn't get executed in the /onreply_route/ /onreply_route[MANAGE_REPLY] {/ /if(is_first_hop())/ /set_contact_alias();  # contact alias doesn't get set?/ /}/ *is_first_hop()* /"The function returns true if the proxy is first hop after the original sender. For incoming SIP replies, it means that top Record-Route URI is 'myself' and source address is not matching it"/ *This is the reply.* 2018/10/03 17:03:38.276846 2.2.2.2:62033 <http://2.2.2.2:62033> -> 1.1.1.1:5060 <http://1.1.1.1:5060> SIP/2.0 200 OK Via: SIP/2.0/UDP sip.mydomain.net:5060;branch=z9hG4bK49b3.bfbe15.0;received=1.1.1.1 Via: SIP/2.0/UDP 10.10.10.10:5060;rport=5060;branch=z9hG4bK1af96136 *Record-Route*: <sip:sip.mydomain.net <http://sip.mydomain.net>;lr=on;did=4cc.734> Contact: <sip:888@10.17.0.35:62033 <http://sip:888@10.17.0.35:62033>>  Suggestions? Thanks. _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users