Q: When I try to ssh to a newly-installed Debathena machine, why does it immediately error with "Connection closed"?

Answer

When you try to connect via ssh to a newly installed Debathena machine, you may get the following error:

$ ssh some-hostname.mit.edu
Connection closed by 18.xxx.yyy.zzz

This is a known bug caused by the interaction between OpenSSH, the debathena-ssh-server-config packages, and Kerberos. This is being tracked in the Debathena bug tracker as Bug #315.

The problem occurs when a machine has previously had a srvtab or keytab, but doesn't currently have one installed.

The easiest way to rectify this is to install a keytab for your machine. Keytabs can be requested (by the machine's owner) at https://ist.mit.edu/accounts/keytab or by contacting the IS&T Service Desk (servicedesk@mit.edu or 617-253-1101) .

As a workaround before the keytab is in place, you can specify -o GSSAPIKeyExchange=no when using connecting to your workstation via ssh.