[Linphone-users] TLS Client Hello Reports Version "SSL 3.0"

[Adam Talbot]

Hi all,
Recently I have tried to set up LinPhone to work with a FreeSWITCH 
server running on the Amazon EC2 Web Service.
I was unable to do this successfully and figured I would share what I 
believed the problem to be.

Note: I have achieved this connection using the CSIPSimple Softphone so 
I am not waiting on a resolution to this issue but getting LinPhone 
working as well.  Also I am willing to help diagnose the issue if it is 
needed.

I was able to register my user with the FreeSWITCH server using UDP but 
when I tried to use TLS the SSL "Client Hello" negotiation would fail 
with "Handshake Failure".
A Wireshark packet capture showed some discrepancy in in the SSL header 
and Client Hello packet:
Secure Sockets Layer
=> Content Type: Handshake (22)
=> Version: SSL 3.0 (0x0300)
...
=> Handshake Protocol: Client Hello
...
===> Version: TLS 1.2 (0x0303)
...

I was successfully able to pass the Client Hello negotiation using both 
CSIPSimple and the opensll s_client feature.
CSIPSimple used version "TLS 1.0 (0x0301)" in both the packet header and 
the Client Hello.
openssl s_client used the two version, "TLS 1.0 (0x0301)" and "TLS 1.2 
(0x0303)" respectively.

Speaking to the FreeSWITCH IRC channel briefly they said SSL 3.0 is not 
supported leading me to believe this is what caused the failure.

I don't know that what LinPhone is doing is a bug per se.  But it is a 
compatibility issue I figured I should report.

Thanks,
Adam.