Re: telnet access on RH7.1

[Eric Koldeweij <eric no-sense net>]

Hi,

The message "could not connect to server" means the connection attempt 
has timed out without any response from the server.
If the box is up and running (which I assume it is :) ) the most 
probable cause is the firewall, or a routing problem.

First you should ping the server, assuming ping is not blocked by the 
firewall. If that responds, the box is reachable from the outside and 
it's not a routing problem.

Then you can check if the telnet service is enabled by doing "netstat 
-ta | grep telnet"
If (one of) the response(s) is:
tcp        0      0 *:telnet                   *:*                     
LISTEN
the box is listening for telnet connects.

You haven't mentioned HOW you set up the firewall. If you wrote your own 
script, make sure there are TWO iptables lines for telnet, like this:
iptables -A INPUT -p tcp --sport "1024:65535" -d 123.123.123.123 --dport 
telnet -j ACCEPT
iptables -A OUTPUT -p tcp ! --syn -s 123.123.123.123 --sport telnet 
-dport "1024:65535" -j ACCEPT
where 123.123.123.123 is your server's IP address.
A common mistake is to forget the second line in the script :)

Last but not least I'd advise to ditch telnet altogether. Using telnet 
is a security risk since everything, including usernames and passwords 
are sent unencrypted over the network. Any trained monkey with a sniffer 
eavesdropping could easily get your passwords that way. Use ssh instead, 
which is included in (at least) every RedHat distro from 7.0 and up (and 
probably even earlier, didn't bother to check)

Just by experience my guess (mind, GUESS) is your problem is 
firewall-related. You did not give much info on your setup though (like 
How you set up the firewall, How you enabled telnet and so) Please give 
as much information as you can, including kernel version, telnet 
version, inetd/xinetd version etc etc etc and contents of related config 
files (like /etc/xinetd.d/telnet, /ets/hosts.deny /etc/hosts.allow etc)

Hope this helps,
Eric.

Larry Burditt/ansci/dasnr/Okstate wrote:

> I'm having problems setting up telnet access.  I have the telnet sever 
> installed and the firewall set to accept telnet access and I've triple 
> checked the IP address but when I try to access the machine I get 
> "could not connect to server".
>
> Larry