How to allow particular user only to login as a root using "ssh" ?

UNIX for Advanced & Expert Users
1

Q1
I want to allow particular user only to login into root using ssh.
I have set PermitRootLogin no for security purpose but I want to allow some of
the users to login as a root using ssh how to do this?

I have tried with Allowusers user1 user2 its working for only the user1 and user2 is allowed to use the ssh connection. others are not able to use the ssh connection.

Q2
I want to run my Perl Script after the ssh connection.?
Where I have to configure this for run my Perl Script ?

2

What O/S are you running ? If it is Linux or Solaris (others may provide the same functionality) then you may be able to tweak the pam.conf to provide this functionality. (see pam_succeed_if.so and pam_deny.so for info)

3

You can exchange the id_rsa.pub certificate of that user to the root autorized_keys file and that�s all.
If not you have to modify conf files to allow access to that user.
Please tell us what OS are you running, to be more specific.

4

for all users? if yes, modify your /etc/profile to run the perl script

if for a specific user, make use of .bash_profile (or its equivalent, depending on the login shell) for that user