Slow Login through SSH

Issue:

Most of us might have observed slowness while logging in to a Linux box though ssh. Though there are various reasons/issues for this, we can fine tune w.r.t ssh config by below changes.

Resolution:

1.) Disable remote host lookup by enabling UseDNS, by default this option is enabled & the line will be commented in /etc/ssh/sshd_config

uncommnet UseDNS & change it to no as below

# vi /etc/ssh/sshd_config
.
UseDNS  no
.
# /etc/init.d/sshd reload


Generally the ssh login will be faster than earlier by the above changes, if still you are facing the same issue you can go for below changes only if you are not using GSSAPI based authentication.


2.) GSSAPI based user authentication needs to be diabled if its not being used

# vi /etc/ssh/sshd_config
.
GSSAPIAuthentication no
.
# /etc/init.d/sshd reload


Note:

Make sure that there is no network level issues like low bandwidth allocated, high bandwidth utilization or connectivity issue :) :)