3CXPhone in dual NIC setup - no audio

[gse]

Hi All,

Our 3CXPhone server is set-up with 2 NICs as follows:

NIC 1: 10.100.0.23/24 << Our SIP phones connect to this NIC
NIC 2: 10.49.39.28/24
Default gateway: 10.100.0.1

Our VoIP provider gives us a dedicated connection and we route to them via NIC2. We have a couple of static routes that go out via NIC 2 to reach their end. Similar to:

203.43.22.1 via 10.49.39.27

The issue we're having is that if we call in, or if we dial out, we get no audio both ways. The phones ring so the SIP session is getting established, but audio doesn't flow.

According to our provider, they are seeing the NIC 1 address in the SIP headers and that's the root of the problem (as opposed to the NIC 2 address). This is what they sent us from their packet trace:

v=0
o=3cxPS 309053095936 213892726785 IN IP4 10.100.0.23 (wrong address)
s=3cxPS Audio call
c=IN IP4 10.100.0.23 (wrong address)
t=0 0
m=audio 7286 RTP/AVP 18
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=sendrecv

Any ideas as to why 3CX Phone might be using the NIC 1 address to talk to our provider which goes out of NIC 2?

Thanks in advance.
GS

 

[craigreilly]

Do you have the correct public ip setup in 3cx?

 

[gse]

I did have the correct IP setup, yes.

I managed to fix it though. I actually followed the last example in the 3CX supported network configurations and the only difference is that we had our static routes (for reaching the VoIP provider) configured using:

route add X.X.X.X etc /P

... as opposed to using RRAS and static routes configured via the GUI. Switched to this now and 3CX started working!? Go figure.