Solve the problem of slow SSH login under CentOS

This problem occurs because the sshd of the server goes to DNS to find the hostname that accesses the client IP, which can take a significant amount of time if the DNS is unavailable or no related records are available.

1. Add the server IP and hostname to the/etc/hosts file on the server

2. Modify or add Usedns=no to the/etc/ssh/sshd_config file on the server

Usually to this point can already solve the problem, if not yet, please do the third part:

3. Comment out all rows in/etc/resolv.conf on the server

4. Modify the hosts in/etc/nsswitch.conf on the server to Hosts:files

The final step is to restart the system.

Solve the problem of slow SSH login under CentOS