phi of n | Some useful technical information for Telephone (Mac OS X Softphone)

phi of n | Some useful technical information for Telephone (Mac OS X Softphone):

Some useful technical information for Telephone (Mac OS X Softphone)

By Maurice13. October 2010 11:41

Telephone has two not so obvious options under Preferences/Network: "Use ICE" and "Use DNS SRV". What do they mean?

In order to find out, I activated Debug logging with defaults write com.tlphn.Telephone LogLevel -integer 4. The log file will be at ~/Library/Logs/Telephone.log.

• "Use DNS SRV" - this is a discovery method. Telephone checks for the followign DNS records: _sip._udp.<domain-as-specified-by-account>. The lookup is tried twice.
• "Use ICE" (ICE = Interactive Connectivity Establishment) - this is a NAT traversal technology (explanation of methodology). Telephone seems to use the pjsip.org pjnath module, andthere ICE uses STUN transport. So checking this option is only useful if you also use STUN. I do not use STUN so I get lot's of messages like icetp00 Creating ICE stream transport with n component(s), icetp00  Comp 1: host candidate <local-ip>:<local-port>, addedicetp04  ICE stream transport created,  and finally icetp07  Too many host candidates.

And last - if you want to transfer Telephone-settings from one computer to another, copy the~/Library/Preferences/com.tlphn.Telephone.plist - but remeber that the account password is saved in keychain under the entry SIP: <name-of-domain>. If this entry is not present, Telephone may not start properly.