Telnet script

Shell Programming and Scripting
1

Hi all,

I would like to write a ad hoc shell script that would allow me to do some telnet tests to multiple IP's and ports at the same time . So, I want to determine which one is successful and which one fails. So, basically I would like the shell to spawn the telnet test and to break out of it when it fails ( Trying to connect for more than 5 sec ) and also break out of it when it succeeds and then move on to the next test.
Let's say for example I would like to run these tests:

telnet 172.27.26.3 2200
telnet 172.89.6.4 443
telnet 172.4.5.6 1200
telnet 172.2.3.4 229
telnet 172.4.3.5 25
telnet 123.5.6.7 443
telnet 229.4.5.6 80
telnet 72.8.7.5 53

2

It must be telnet?

If you can use ssh, you can try:

sshOptions="-oPort=22 -oPreferredAuthentications=publickey -oPubkeyAuthentication=yes -oKeepAlive=yes -oConnectionAttempts=1 -oNumberOfPasswordPrompts=1 -oStrictHostKeyChecking=no"
echo "Test" | ssh -T -C ${sshOptions} -l ${remoteUser} ${remoteHost} 1> /dev/null 2>&1

You have several ssh option: UNIX man pages : ssh (1)

For the user/password, not to ask it while executing the script, check: OpenSSH Public Key Authentication

Regards.

---------- Post updated at 15:28 ---------- Previous update was at 15:08 ----------

One comment I forgot is to test the ssh return code after execution:

echo "Test" | ssh -T -C ${sshOptions} -l ${remoteUser} ${remoteHost} 1> /dev/null 2>&1
sshReturnCode=$?

if [ ${sshReturnCode} -ne 0 ]
then
      echo "ERROR: Failed to access host:[ ${remoteHost}]."
fi
3

It will not be access to some machine. It will be telnet to some applications. Like telnet to see if I can reach www.google.com to see if I have good connectivity.

4

Ok!

We have two options:

With "expect":

#!/usr/local/bin/expect 
spawn telnet <machine ip> 
expect "login:" 
send "<username>\n" 
expect "Password:" 
send "<password>\n" 
send "bash\n" 
send "cd /opt\n" 
send "ls -ltr\n"
interact

How to execute the �expect� command expect �f <file name>

expect �f <filename>.expect

If you are in a linux box, or in your Unix distribution you have: "autoexpect", it creates an "expect" script for you. Check this link: autoexpect

==========================
Or, there is a post here that shows a way to use telnet:

http://www.unix.com/shell-programming-scripting/11359-need-script-passwd-cant-use-expect-tool-post40791.html\#post40791

I hope it helps!

Regards.