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Top Forums UNIX for Beginners Questions & Answers Ssh script to validate ssh connection to multiple serves with status Post 303018342 by rbatte1 on Monday 4th of June 2018 09:30:18 AM
Old 06-04-2018
Depending how many you are poking, you might consider these adjustments too:-
Code:
#!/bin/bash
for host in $(cat servers.txt)
do
        ssh -q -o ConnectTimeout=3 "$host" "hostname"
done > test.log

The blue -q is to suppress some of the normal output to keep your log file a little clearer, however the log file will probably still collect anything that is displaed by the server login process e.g. from /etc/profile or ~/.bashrc

I've added the green to speed up the timeout if the server does not respond. You might want to adjust it depending on what your network will allow.

The red hostname is a command to run on the server you are connecting to. You have $HOSTNAME which may be undefined or set to anything in the shell's environment prior to this script.


What output do you actually want? Is it a list of hosts you could not connect to? If you can open the IP connection, but if fails to sign in how would you handle that? You script would probably just hang. Other conditions may cause your script to carry on to the next host immediately, e.g. the server's public key is different and you get an alert about a possible man-in-the-middle attack. The ssh exits with a non-zero return code, but you don't check. Perhaps you just want a list of successes to then target those that don't let you connect. Knowing the goal would be useful for us.



Robin
 

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SSH-COPY-ID(1)						      General Commands Manual						    SSH-COPY-ID(1)

NAME
ssh-copy-id - install your public key in a remote machine's authorized_keys SYNOPSIS
ssh-copy-id [-i [identity_file]] [user@]machine DESCRIPTION
ssh-copy-id is a script that uses ssh to log into a remote machine and append the indicated identity file to that machine's ~/.ssh/autho- rized_keys file. If the -i option is given then the identity file (defaults to ~/.ssh/id_rsa.pub) is used, regardless of whether there are any keys in your ssh-agent. Otherwise, if this: ssh-add -L provides any output, it uses that in preference to the identity file. If the -i option is used, or the ssh-add produced no output, then it uses the contents of the identity file. Once it has one or more fin- gerprints (by whatever means) it uses ssh to append them to ~/.ssh/authorized_keys on the remote machine (creating the file, and directory, if necessary.) NOTES
This program does not modify the permissions of any pre-existing files or directories. Therefore, if the remote sshd has StrictModes set in its configuration, then the user's home, ~/.ssh folder, and ~/.ssh/authorized_keys file may need to have group writability disabled manu- ally, e.g. via chmod go-w ~ ~/.ssh ~/.ssh/authorized_keys on the remote machine. SEE ALSO
ssh(1), ssh-agent(1), sshd(8) OpenSSH 14 November 1999 SSH-COPY-ID(1)
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