how to prevent same user ssh to the multiple server
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Thank you for the reply , but this MaxSessions is applicable for 1 single server ?I need it to cross check betweens servers , so if User A logged in to Server 1 they can't log in to Server 2 .
There's no (built-in) way I know of; why would you want this anyway?
I am trying to prevent the same user to log in to multiple server at one time .Is there anyone know came across this problem ?Is there anyway we can make the server to check across servers before allowing the user to log in ?
I haven't heard of a function like that being build in. In my opinion a minimum requirement in order to have something like this available is to have a centralized authentication system like LDAP. Or you can write a script that checks logged in users on other servers before allowing login, but I imagine that would be quite an undertaking. As asked by chrism01, why would you want this feature? What's the need for it?
I am trying to prevent the same user to log in to multiple server at one time .Is there anyone know came across this problem ?Is there anyway we can make the server to check across servers before allowing the user to log in ?
I need some help on how to prevent same user from ssh to multiple linux server at a same time , anyone of you have the script or how to do that ?
Really appreciate it !
Thanks and best regards.
Steve
Hi,
I have a workaround for this. I am not sure whether this is the best way, But yes it works pretty good. I tested this in RHEL 5.0
For this, I have made a file/tmp/users in which I have entries of the users for which I need to check.
AND /tmp/check_ssh.sh which is my script.
You just need to run this script in background as
Code:
(bash /tmp/check_ssh.sh &> /dev/null) &
and put usernames of the users in /tmp/users
My files...
Code:
[root@server ~]# cat /tmp/check_ssh.sh
#!/bin/bash
while [ 1 ];
do
for user in `cat /tmp/users`;
do
top -u $user -bn1 | grep -w ssh
if [ $? -eq 0 ]
then
setfacl -m u:$user:000 /usr/bin/ssh
else
setfacl -x u:$user /usr/bin/ssh
fi
done
done;
[root@server ~]# cat /tmp/users (Here a,b,c are the users)
a
b
c
[root@server ~]#
Now, whenever a user initiates a second ssh session, he gets the below error.
I have a workaround for this. I am not sure whether this is the best way, But yes it works pretty good. I tested this in RHEL 5.0
For this, I have made a file/tmp/users in which I have entries of the users for which I need to check.
AND /tmp/check_ssh.sh which is my script.
You just need to run this script in background as
Code:
(bash /tmp/check_ssh.sh &> /dev/null) &
and put usernames of the users in /tmp/users
My files...
Code:
[root@server ~]# cat /tmp/check_ssh.sh
#!/bin/bash
while [ 1 ];
do
for user in `cat /tmp/users`;
do
top -u $user -bn1 | grep -w ssh
if [ $? -eq 0 ]
then
setfacl -m u:$user:000 /usr/bin/ssh
else
setfacl -x u:$user /usr/bin/ssh
fi
done
done;
[root@server ~]# cat /tmp/users (Here a,b,c are the users)
a
b
c
[root@server ~]#
Now, whenever a user initiates a second ssh session, he gets the below error.
Just test this, and tell me if you face any issues.
Sweet , i am going to test this out , may i know to make this applicable for multiple server checking ?If let say i have server A , B , C , how can i make it only to allow User log in to any server at a point of time ?
I have done this only, if a user logs in to server A, he would not be able to login to server B or C, until he logout from server A.
I have tested this code on my machine. Waiting for your response.
i am sorry , I think i didn't myself clear enough .Your script is good to prevent user ssh to Server B inside Server A .
What i am actually looking for is to stop user from opening a new ssh session to connect to any other servers if they are already connected to anyone .
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