I had a problem with very long logging via ssh to my servers (Fedora 16 and Centos 6). After testing some configuration I discovered that the problem is in enabled GSSAPIAuthentication options. After hashing this GSSAPIAuthentication connecting to ssh is very fast. I am wondering is turning off GSSAPIAuthentication good idea. Is there a good reason to not disabling it??
GSSAPIAuthentication is merely a directive that enables an alternative authentication option. Examples of other authentication options would be keyboard-interactive (typing your password) or SSH keys. If you aren't using GSSAPI then there is no downside to disabling it.