Slow SSH Login

OS: centos 6.5

Kernel version: 2.6.32-431.23.3.el6.x86 _ 64

 
[[Email protected] ~] # Ssh-vopenssh_5.3p1, OpenSSL 1.0.1e-FIPS 11 Feb 2013
 

There are two reasons for slow SSH:

1. Usedns opening Problems
   

2. Gssapiauthentication

Modify/etc/ssh/sshd_config

 
Sed-I "s/# usedns Yes/usedns no/g"/etc/ssh/sshd_configsed-I "s/gssapiauthentication Yes/gssapiauthentication no/g"/etc/ssh/sshd_config'
 

The preceding two commands change usedns yes to No. Generally, the OpenSSH server performs dns ptr reverse query on the client's host name based on the client's IP address, then, based on the queried client host name, perform DNS forward a record query and verify whether the query is consistent with the original IP address. This method prevents Client Spoofing, because most of our network environments are dynamic IP addresses that do not have PTR records, this item does not have much effect.

Gssapiauthentication whether to allow the use of gssapi-based user authentication is now disabled, used only for SSH-2.GSSAPI is a universal security service application interface, an application interface to allow the program to access security services. Close it.

This article from the "Fenglin late" blog, please be sure to keep this source http://fengwan.blog.51cto.com/508652/1542391