Telephone picking wrong network interface

[Ilya Semenov]

I've run into the following issue:

1) Calls to and from servers in the internet all work flawlessly

2) Calls via a Freeswitch server (which is inside our LAN) to a user which is also in our LAN work.

3) Calls via a Freeswitch server (which is inside our LAN) from a user which is also in our LAN do not work.

My IP address is 10.0.2.46, the server IP address is 10.0.3.1, the netmask is /16, the default gateway is 10.0.1.2, everything is reachable directly, there's no weird routing and such.

I was investigating and I discovered that Freeswitch is trying to reach me at sip:10...@10.211.55.2:52402

I also discovered that when Telephone registers at the SIP server, it sends this: '"Ilya Semenov" <sip:10...@10.211.55.2:52402;ob>' as contact name.

I do have a network interface on my Mac with that IP address 10.211.55.2 (I think it comes with Parallels Desktop) but it's a different network so no surprise that the calls don't reach me.

Obviously, Telephone works incorrectly here, it should have picked the proper interface automatically based on the destination IP address and the system routing rules.

So question: is there a way to tell Telephone which IP address (interface) to use when it registers at a SIP server? Or any other advice?

[Lars Trebing]

On Thursday, November 1, 2012 3:42:51 PM UTC+1, Ilya Semenov wrote:

I was investigating and I discovered that Freeswitch is trying to reach me at sip:10...@10.211.55.2:52402

I also discovered that when Telephone registers at the SIP server, it sends this: '"Ilya Semenov" <sip:10...@10.211.55.2:52402;ob>' as contact name.

I do have a network interface on my Mac with that IP address 10.211.55.2 (I think it comes with Parallels Desktop) but it's a different network so no surprise that the calls don't reach me.

I stumbled upon the same issue here. Telephone stopped working on my main computer (running 10.8) a while ago, but works fine on two other Macs (10.6 and 10.7), so I first suspected it might be a Mountain Lion issue. Then I turned Telephone’s debug logging feature on and found the same issue that you described: Telephone tells the SIP server to reach it at 1.1.1.1 (a VirtualBox interface in my case). Disabling this interface (ifconfig vboxnet1 down) before starting Telephone is a possible workaround but obviously not a very viable one.

I took a brief look at the Telephone sources and saw that it mostly relies on PJSIP 1.12 (<http://www.pjsip.org/>) for this kind of stuff, so this is probably an issue with this library. Interestingly, the PJSIP wiki says that they are using an algorithm here that seems to make sense (cf. <http://trac.pjsip.org/repos/wiki/FAQ#multihomed>) and certainly doesn’t look like something that would lead to such a strange behavior. Hmm …