How to Telnet into a Shell Account

Even though you can't telnet into an account inside some computer, often you can get some information back or get that computer to do something interesting for you. Yes, you can get a telnet connection to succeed -without doing anything illegal --against almost any computer, even if you don't have permission to log in. There are many legal things you can do to many randomly chosen computers with telnet. For example:
C:/telnet freeshell.org 22
SSH-1.99-OpenSSH_3.4p1
That tells us the target computer is running an SSH server, which enables encrypted connections between computers. If you want to SSH into an account there, you can get a shell account for free at
. You can get a free SSH client program from
.
One reason most hackers have shell accounts on Internet servers is because you can meet the real hackers there. When you've logged in, give the command w or who. That gives a list of user names. You can talk to other users with tht talk command. Another fun thing, if your shell account allows it, is to give the command
ps -auxww
It might tell you what commands and processes other users are running. Ask other users what they are doing and they might teach you something. Just be careful not to be a pest!
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You can get punched in the nose warning: Your online provider might kick you off for making telnet probes of other computers. The solution is to get a local online provider and make friends with the people who run it, and convince them you are just doing harmless, legal explorations.
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Sometimes a port is running an interesting program, but a firewall won't let you in. For example, 10.0.0.3, a computer on my local area network, runs an email sending program, (sendmail working together with Postfix, and using Kmail to compose emails). I can use it from an account inside 10.0.0.3 to send emails with headers that hide from where I send things.
If I try to telnet to this email program from outside this computer,
here's what happens:


C:\>telnet 10.0.0.3 25
Connecting To 10.0.0.3...Could not open connection to the host, on
port 25.
No connection could be made because the target machine actively
refused it.
However, if I log into an account on 10.0.0.3 and then telnet from
inside to port 25, here's what I get:
Last login: Fri Oct 18 13:56:58 2002 from 10.0.0.1
Have a lot of fun...
cmeinel@test-box:~> telnet localhost 25
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1... [Carolyn's note: 127.0.0.1 is the numerical
address meaning localhost, the same computer you are logged into]
Connected to localhost.
Escape character is '^]'.
220 test-box.local ESMTP Postfix
The reason I keep this port 25 hidden behind a firewall is to keep
people from using it to try to break in or to forge email. Now the
ubergeniuses reading this will start to make fun of me because no
Internet address that begins with 10. is reachable from the Internet.
However, sometimes I place this "test-box" computer online with a
static Internet address, meaning whenever it is on the Internet, it
always has the same numerical address. I'm not going to tell you what its Internet address is because I don't want anyone messing with it. I just want to mess with other people's computers with it, muhahaha. That's also why I always keep my Internet address from showing up in the headers of my emails.
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Newbie note: What is all this about headers? It's stuff at the
beginning of an email that may - or may not - tell you a lot about
where it came from and when. To see full headers, in Outlook click
view -> full headers. In Eudora, click the "Blah blah blah" icon.
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