Inbound/Outbound proxy mixup, incorrect SIP headers?

[Daikoku]

Hi,

I'm having an issue with Vitelity as they require a different proxy for inbound and outbound.
Vitelity says:

Inbound = sip24.vitelity.net
Outbound = outbound.vitelity.net

So I went ahead and in 3cx console I set:

SIP server hostname or IP = sip24.vitelity.net
Outbound proxy hostname or IP = outbound.vitelity.net

Now when I do a wireshark trace, I see that the traffic correctly goes to outbound.vitelity.net but the header is for the inbound header?

71 4.636552 192.168.1.250 outbound.vitelity.net SIP 427 Request: ACK sip:[email protected]:5060

Anyone has an explanation for this, why is the traffic sent to the right server with the inbound SIP header?

Thanks!

 

[Daikoku]

I see the same issue on the REGISTER packets - inbound and outbound are mixed up:

1958 102.988398 192.168.1.250 outbound.vitelity.net SIP 828 Request: REGISTER sip:sip24.vitelity.net:5060

 

[Daikoku]

anybody has any idea?

 

[danhriscanu]

Hi,

This is not a mix up.
sip24.vitelity.net its your sip server and outbound.vitelity.net is your outbound proxy.
Your SIP address should be like [email protected] and the packets for registration should be send to that server.
What is your problem? What is not working?

 

[Daikoku]

Initially I had an issue with inbound calls not working on Vitelity and Vitelity support said that the reason is that 3CX sends the REGISTER to the outbound proxy rather than the SIP server.

They suggested that I set the outbound proxy to sip24.vitelity.net and by doing so the inbound calls started working as the REGISTER packets now went to sip24.vitelity.net

The problem with that though is that outbound calls now also go to sip24.vitelity.net rather than outbound.vitelity.net, which works occasionally but more often than not I'm getting a 603 Forbidden.

 

[danhriscanu]

I think this issue is from your provider. Try to put outbound proxy the same as your SIP server. The outbound proxy, if its different should only help passing the packet to SIP registrar. If this doesn't work you should speak with your provider to try to solve this.

 

[Daikoku]

I tried this but then it appears the register fails and I'm not getting any inbound calls.

I'm not really too familiar with SIP but per specs, is it correct to send the REGISTER packets to the outbound proxy address? My assumption would be that only outbound calls should be sent to the outbound proxy but the REGISTER packets should go to the SIP address?

 

[danhriscanu]

Yes! You are right. The REGISTER packets should be sent to SIP server. That is why I told you to put only SIP server address in the Outbound proxy field. If it doesn't work contact your SIP provider to solve this issue. Keep in mind that 3cx Phone System does not mix up SIP header and it does exactly what you tell it to do.

 

[Daikoku]

Sorry but what you are saying doesn't make any sense to me. I'd expect the REGISTER packet to go to the server entered as SIP server, regardless of what is set as outbound proxy. Anyways, Vitelity support was helpful and re-provisioned my account to another server that supports in and outbound calls, thus solving the issue.