Hi, I just tried to use kamailio 5.8.3 as an IMS-PCSCF. After handling SIP registration, it seems that value of port in the "via" header in the request sent from PCSCF to UE is a bit strange. When using uac_req to send OPTIONS to UE, it is found that in the OPTIONS sent out from kamailio, the value of port inside the "via" header is set to port_pc (pcscf ipsec client port). Is this correct? Or should the via header port be set to port_ps (pcscf ipsec server port) instead? Also, in uac_req, is the value of via port header configurable? Please advise. Thank you. Regards, Hong