Urgent: sshd setup

swmok · 04-08-2005, 09:16 PM

Hello:

I want to setup the sshd such that it allows the root login(or a specific user) ONLY.

How to do that?

Many thanks.

swmok

Joey.Dale · 04-08-2005, 09:27 PM

One: Just because something is Urgent to you, doesn't mean its Urgent to everyone else.
Two: Please be more spicific
Three: read

Code:

man ssh_config

Four: Google is your friend.
Five: Please search before posting as I'm sure this has been asked before.

-Joey

swmok · 04-08-2005, 09:44 PM

First:
"Urgent" must be urgent to me. How can I know whether it is urgent to you?
I just want to express my feeling about my situation. Shouldn't I do this?

Second:
"Be specific". What's your point? How am I "non-specifie"? Pls. be specific to me.

Third:
I am asking about the setup of sshd. NOT ssh client.
I've read the file sshd_config.
There is a field to allows the login from a specific host NOT a specific user.

Fourth:
Thanks for your advice. However, could you pls. be more specific?
What keywords should I input?

Fifth:
How can you know "I haven't search the web."?
I just don't know how to search what I want.

Sixth:
If you're willing to help, just skip the post.
No need to blame others.
If you think the post is nonsense, talk to the admin. and kill this post.

Joey.Dale · 04-08-2005, 09:59 PM

Code:

echo "AllowUsers root" >> /etc/ssh/sshd_config

Where did I find that? In the sshd_config man page:

Quote:

AllowUsers
This keyword can be followed by a list of user name patterns, separated by spaces. If specified, login is allowed only for user names that match one of the patterns. `*' and `?' can be used as wildcards in the patterns. Only user names are valid; a numerical user ID is not recognized. By default, login is allowed for all users. If the pattern takes the form USER@HOST then USER and HOST are separately checked, restricting logins to particular users from particular hosts.

-Joey

swmok · 04-08-2005, 10:18 PM

To Joey.Dale:

I apologize for my rudeness. Your help is so precious to me.

My urgent situation is that:
I am an admin of a over-100-user computer. 70% of them know nothing about computer and
their password is same as their username(So stupid, right?).
In the past few days, there are some hackers login to the computer and ruined the system.
I've just reinstall it and find the hackers AGAIN.

Your help let me know how to block these hackers and still allowing to do the admin job.

Thanks a lot and please accept my sincere apology.

swmok

zeos · 04-08-2005, 10:29 PM

Personally, I'd start by kicking my users squarely in their foreheads one at a time....

Then Setup public/private key auth for a non root user and only allow that user to logon via ssh with the AllowUsers directive. Then, add that user to the wheel group and set "su" to be executable only to users in "wheel" and root

Then you could log in with that user, using a rsa key/passphrase combo and su to root as needed