Tell me about Telnet, what's the scoop these days?

jols

Well-Known Member
Mar 13, 2004
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Just got a new cPanel server, but it did not have telnet installed. So I installed it with:

yum install telnet

I need it for performing tasks like the following at shell:

telnet somemailserver.com 25 (to see if port 25 is accepting connections).

But then I remembered all the dire warnings about now un-secure telnet is. So I went for my very old instructions to disable telnet, which are still commonly given out, but these do not work:

pico -w /etc/xinetd.d/telnet
change disable = no to disable = yes
Save and Exit the file and then type below command:
/etc/init.d/xinetd restart


After doing:
pico -w /etc/xinetd.d/telnet

I get pico just opening a new file, i.e. there are no telnet settings there.

So what's the scoop on telnet these days? I use SSH but only with encryption keys, no password access to shell is available. In this situation is telnet still dangerous? Or even if I had password SSH access going, would telnet be dangerous then? And where are the telnet configs these days?

So may questions, so few corn chips.
 

mtindor

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Sep 14, 2004
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Just because you installed the telnet client [package "telnet"] doesn't mean you installed the telnet server [package "telnet-server"].

You likely don't have the telnet service installed, just the client.

M
 

quietFinn

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Feb 4, 2006
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You installed telnet client, not the telnet server.

AFAIK it's no problem to have the telnet client installed, it's the telnet server you shouldn't have.
 

jols

Well-Known Member
Mar 13, 2004
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Okay, thanks. So if yum install telnet does not install the telnet server, I would think then that I'm okay with security, in this regard.

Thanks again for the replies.
 

mtindor

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Sep 14, 2004
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Okay, thanks. So if yum install telnet does not install the telnet server, I would think then that I'm okay with security, in this regard.

Thanks again for the replies.
That's probably safe to assume. Do a 'netstat -an|grep '\:23' and see if you have any listeners on TCP 23. If you don't, then you're likely safe.

M
 

quietFinn

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Feb 4, 2006
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And you can also check that TCP IN port 23 is closed.