[kwlug-disc] Dump skype on Monday night

Jason Locklin locklin.jason at gmail.com
Wed Jun 8 11:41:19 EDT 2011

On Wed, 2011-06-08 at 00:00 -0400, Bob Jonkman wrote:
> Well, John Kerr and I tried to use SIP softphones, but it seems the 
> LOL-security was just too strict.
> I was using the Linphone client with my Ekiga account ( 
> BobJonkman at ekiga.net ), and could make an out-bound call to the Ekiga 
> callback test number ( sip:520 at ekiga.net ) but could not receive the 
> callback.
Something to note: some providers (e.g., sip2sip, Skype) have proxy
servers that the client can fall-back on as a last resort to work around
NAT problems. Ekiga.net is a registrar only and does not have proxy

> John and I tried to make a peer-to-peer connection, but that was also 
> unsuccessful.  Perhaps the softphones need to make contact with a server 
> before handing off in a p2p session.
Dialing the other person's ip address (or using Bonjour/ZeroConf rather
than his sip URI) should  work as long as you can ping each other, but
if you are both behind the same NAT ip address and calling each other
via your ekiga.net addresses, it often won't work (you both appear to be
at the same ip address to ekiga.net, so it can't establish a route). In
fact, NAT traversal tricks like STUN can actually hamper establishing a
connection because the softphone will report the NAT ip address to the
server rather than the local ip. You can try disabling any STUN/network
detection settings in your client, or using a client that has a smarter
network stack that implements ICE.

It would be great to try a bunch of softphones on a variety of networks
to see if any of them actually manage to work consistently across the
various situations that typically arise for a laptop user. 

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