Hello,

I'm using Kamailio ver. 5.8.4.

I configured the ims_ipsec_pcscf with

modparam("ims_ipsec_pcscf", "ipsec_max_connections", 1)

and call ipsec_forward with flag = IPSEC_FORWARD_FLAGS

where :

# - IPSEC_SEND_FORCE_SOCKET 1

# - IPSEC_FORWARD_USEVIA 256

#!define IPSEC_FORWARD_FLAGS 257

For the UE REGISTRATION I have the following flow

UE                                        PCSCF_GM_IMS                      

                  REGISTER                                          

(32133)         ------------------>     (5060)                

                  100 Trying                                         

(32133)         <------------------       (5060)                  

                  401 Unauthorized                                

(32133)       <------------------      (5060)                  

                  REGISTER        (TCP)                          

(PORT_UC)  ------------------>     (PORT_PS)             

                  100 Trying       (TCP)                           

(PORT_UC)   <------------------     (PORT_PS)            

                  200 OK            (TCP)                           

(PORT_UC)   <------------------     (PORT_PS)            

------------------------------------------------------------------

                  SUBSCRIBE      (UDP)                         

(PORT_UC)   ------------------>      (PORT_PS)           

                  200 Subscription (UDP)                       

(PORT_US)   <------------------     (PORT_PC)              

                  NOTIFY            (UDP)                           

(PORT_US)   <------------------     (PORT_PC)               

                  200 OK            (UDP)                            

(PORT_UC)   ------------------>     (PORT_PC)              

                  NOTIFY            (UDP)                          

(PORT_US)   <------------------     (PORT_PC)      

                  200 OK            (UDP)               

(PORT_UC)   ------------------>     (PORT_PC)      

                  NOTIFY            (UDP)               

(PORT_US)   <------------------     (PORT_PC)     

                  200 OK            (UDP)               

(PORT_UC)   ------------------>     (PORT_PC)      

The SUBSCRIBE behavior is correct : PCSCF receives message on PORT_PS and sends on PORT_PC

The NOTIFY behavior is wrong: PCSCF send from PORT_PC (correct), but UE respond towards PORT_PC, defined in the Via of the NOTIFY.

I know I can use the set_advertised_port() function, and in this case can work, but the function is taking a constant as a parameter, not a variable. This is causing a problem

when ipsec_max_connections > 1. In that case it won't be easy to pass the correct port.

I was wondering if the ipsec module should properly set the VIA port to the correct PORT_PS, rather than leaving the setting of the correct port by the kamailio.cfg.

Do you have any hints on that?

Thanks