Automatic telnet ( non-interactive telnet) within Unix servers

[anil_garg5]

HI Group,
I have an urgent requirement to automatic telnet few Linux and Unix servers through some script and then run a health status check script.

I have tried a Perl based script.
============================================
#!/usr/bin/perl -w
# perl telnet1.pl username password hostname
use Net::Telnet;
# Get number of command-line arguments.
$num_args = scalar( @ARGV );
if ( $num_args < 2) {
die "Usage: username password hostname\n";
}
$username = shift;
$password = shift;
$hostname = shift;
$tel = Net::Telnet->new(Host => $hostname,
Input_log => ‘telnet.txt’,
Timeout => 30 );
$tel->login($username, $password)
or die "Unable to establish telnet connection $!";
# Issue a command on the remote system.
@df_result = $tel->cmd("df");

foreach $line (@df_result) {
print "$line";
}
$tel->close();
# telnet1.pl
===============================================
$perl telnet1.pl username password hostname
this script is working on non-interactive telnet with localhost but did not connecting with remote hosts.
Please guide what I need to modify here or if someone is using any script for such situation,PLEASE PLEASE send me.

Thanks a lot ..........
Anil
anil_garg5@yahoo.com

[Ivan Ferreira]

I think that will be better and maybe more secure to setup a ssh connection with public keys and no passphrase. You can use the PermitRootLogin forced-commands-only option. And then you can use ssh to get the status of the remote server.

[anil_garg5]

Thanks for your reply....
Only the telnet service is configured in all the remote servers. ssh service is disaled in all the server, so I have no choice..How can tackle this in present situation? Please guide.

[Sergejs Svitnevs]

It is also usefull to check that:

1) telnetd is installed and running on your remote Linux&Unix machines.

2) Your mgmt host is allowed to connect to all remote hosts (add "in.telnetd:" to the bottom of the /etc/hosts.allow file on all hosts).

Regards,
Sergejs

[Ivan Ferreira]

What is the error that you get, can you interactively telnet to the remote host?

[Bill Thorsteinson]

I would seriously consider installing sshd
where it is missing.

If you want to do health checks then
seriously consider installing nagios
or one of the programs of its ilk.

Both options are much more secure.

Also if you are connecting as root, this
may be prevented (quite rightly) by
/etc/securetty, or a similar file.

[anil_garg5]

Thanks a lot all.
I have installaed sshd on Linux machine.
but unable to install sshd on the Solaris machine.I am still working on it.

Thanks,

[Muthukumar_5]

For automation you can try with,

a) expect
b) telent + piping() as,

(
echo "root"
sleep 2
echo ""
sleep 2
echo "command to execute"
sleep 2
echo "exit"
) | telnet machine

--
Muthu

[Muthukumar_5]

Problem is,

sometime telnet service is not enabled in all machines of *NIX. It depends upon your machines. Try to check all the machines for common login service availablity. Then automate with perl or expect scripting or telnet + piping.

--
Muthu

[Alan_152]

You might want to look into using EXPECT, withg either telnet or ssh.

[Stephen Barratt]

One alternative to public keys and no passphrase is to use keychain. On login, you're asked for your passphrase once, then keychain handles authentication after that. You don't need to input your passphrase again unless you reboot.