Hello,

I am having problems generating a valid HMAC key for my TURN allocate requests to the Lync edge server.  I have a valid username / realm / password combination but I always get an error back from the Edge server about the value of the MESSAGE-INTEGRITY attribute.  http://msdn.microsoft.com/en-gb/library/dd949398(v=office.12).aspx

I have had no problems before when generating the MESSAGE-INTEGRITY of STUN messages to other TURN servers, and have come across similar issues with signing STUN messages for interop with Lync (which I have overcome).  I am aware that the TURN message must be padded with NULLs until it is a multiple of 64 before the signing occurs, and that the key for signing is the MD5 hash of USERNAME : REALM : PASSWORD (where the username / password are acquired from the MRAS request, and the realm is from the 401 response from the TURN server).

I have enabled logging on a Lync client and used Wireshark to get the STUN packets it is sending to the Lync TURN component.  I have constructed a test STUN packet to be identical to the one Lync sends, but I am unable to generate the same HMAC as it gets (signing my test packet with the Lync client's username/password from it's MRAS credential response).

Has anyone had any problems getting a valid MESSAGE-INTEGRITY value for the Lync edge server, and if so what was the solution? 

Thanks,

Simon

Hi,

The issue is more related to Lync development. you may post a question on MSDN forum and more lync development expert will help you. Thank you for your understanding.

http://social.msdn.microsoft.com/Forums/en-US/communicatorsdk/threads

Hi Simon,

I have encountered exactly the same problem, tried so many ways to get it right, but failed!

Have you finish the problem?

Can you give me some advice?

Thank you for helping me!