long delay when logging in with CentOS7
/etc/ssh/sshd_config on the remote server you should change the option
GSSAPIAuthentication to no. Restart sshd and you should be good to go.
edit: GSSAPI (Generic Security Service Application Programming Interface) is essentially an API that utilises Kerberos libraries to provide strong network encrypton. Unless there is a particular reason why you need GSSAPI enabled this method should resolve the issue you are having.
edit2: For clarity, it may also be possible that the reverse DNS check is timing out (specifically checking the connecting hosts' PTR record) . SSH does this check as a matter of course because it acts as a security measure to validate the connecting host.
Saying that, the process does not add much in terms of real security because realistically there's a significant proportion of hosts that do not have a PTR anyway. There are three ways to fix this issue:
1). You can amend the
sshd_config file to use the
UseDNS no parameter. This will stop the reverse DNS lookup. It is safe to do.
2). Add a PTR record in the appropriate DNS system for the host that's slow in connecting.
3). Add a manual entry into the OS
hosts file with the relevant entry.
Hope that helps!
This sounds like a DNS issue - during a log-in attempt, a reverse DNS lookup is performed to provide the remote hostname in the auth logs.
Check to ensure that the server does not have an unresponsive resolver in the