telnet

[Rick Stevens]

Rick Stevens wrote:
> roland brouwers wrote:
> 
>> Hi everybody,
>>
>> I have fedora core3 installed on my server
>> I try to login with telnet, having installed :
>> telnet-server-0.17-30.i386.rpm The service telnet is on in chkconfig
>> –list When I login I can enter my login name and password and then he
>> returns me Last login : tue …..from 192.1.1.122 And he stops
>> When I wait long anough it gives me the prompt $
> 
> 
> I can't speak to that specifically, but the most common cause of that
> is a faulty DNS setup.  The machine you're logging into is trying to
> reverse-resolve your IP address so it can log where you connected from.
> It has to wait for DNS to either resolve or time out, and that can take
> up to 136 seconds (65.536 seconds per timeout, 5 seconds between tries,
> two retries, see "/usr/include/resolv.h").  Make sure the remote system
> accesses its DNS server correctly.  If reverse DNS is not available and
> you use a consistent IP address, add it to the /etc/hosts file.

I forgot to mention that, unless you have absolutely no choice, you
should NEVER, EVER use telnet.  Since telnet transmits everything in
cleartext (INCLUDING your passwords), you should never use it unless you
can absolutely guarantee the security of your network--and even then you
should be very, very concerned that someone is snooping your network--
especially if there is a wireless link in it somewhere.

We all recommend you use ssh (secure shell), which encrypts everything
(passwords, text, everything) using one of several different ciphers
(typically blowfish, CAST128, 3DES or Arcfour) and guarantees integrity
of the connection using hmac-md5 or hmac-sha1.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-            The gene pool could use a little chlorine.              -
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