When using MIT Kerberos Ticket Manager with PuTTY 0.65 and WinSCP 5.9.3, I am sometimes unable to get a connnection to the server I am logging into. PuTTY will respond with either No supported authentication methods available (server sent: ) or No supported authentication methods available (server sent: publickey,gssapi-keyex,gssapi-with-mic)

It seems to happen most often if I try to connect to the server before remembering to obtain a ticket first. After getting a ticket, I will keep getting the same error every time I try. It sometimes resolves itself after about an hour.

The connection to both the authentication server and the server I'm trying to connect to operates over a VPN.

I don't get any issues when using Cygwin + kinit.

Here's my log:

. 2017-01-28 14:04:38.979 Server offered these authentication methods: publickey,gssapi-keyex,gssapi-with-mic
. 2017-01-28 14:04:38.980 Using SSPI from SECUR32.DLL
. 2017-01-28 14:04:38.980 Attempting GSSAPI authentication
. 2017-01-28 14:04:39.008 GSSAPI authentication initialisation failed
. 2017-01-28 14:04:39.008 No authority could be contacted for authentication.The domain name of the authenticating party could be wrong, the domain could be unreachable, or there might have been a trust relationship failure.
. 2017-01-28 14:04:39.008 Disconnected: No supported authentication methods available (server sent: )
* 2017-01-28 14:04:39.060 (EFatal) Disconnected: No supported authentication methods available (server sent: )

Check your DNS settings when the problem is reproduced runing ipconfig /all. Among DNS servers should not be anyone who does not know about the domain to which your server.

You can check this by run for each DNS server ip:

nslookup -type=srv _kerberos._tcp.<your server REALM> <DNS server ip>

If the query does not return any entries for some servers - try to remove this server from your settings, clean DNS cache (ipconfig /flushdns) and retry connection.

I don't get any issues when using Cygwin + kinit.

I believe that Cygwin uses own DNS configuration from /etc/resole.conf so to him the problem does not play.

  • Excellent answer, especially with the nslookup command debugging hint. It did turn out to be a DNS issue. My ISP's DNS is unreachable through the VPN so unless I contact the Kerberos realm before tunnel my connection, the lookup will time out. Changing my DNS servers to Google's public DNS works well. – Chris Watts Feb 6 '17 at 14:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.