> I'm currently running Red Hat Linux v3.0.3 and cannot telnet to my
> machine from a different host after about 60 minutes of up time. If at
> the server terminal I can telnet to anywhere and have access to the
> internet, but no one can telnet into my machine from any other host.
> Any ideas? I'm also using a 3Com 3c503.
Have a look at your /etc/inetd.conf file. Are you using the tcp wrapper
tcpd for inetd services like the telnetd. If you are you should have
line like this in the inetd.conf file for telnetd:
telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd
If this is the case, then have a look at /etc/hosts.allow and
/etc/hosts.deny to see if you are allow certain domains in and denying
certain domains. You should be able to do a man on tcpd to learn more
about the tcpd wrapper and how it works.
You may notice that you cannot telnet into your machine as root. (The
fact that you cannot telnet in as other users is odd and perhaps a
configuration thing). If you cannot telnet in as root, that is probably
because of the /etc/securetty file. This file lists the tty's that root
is allowed to come in on. Do a man on securetty.
Also, have a look at the log file /var/log/secure and /var/log/messages
Hope this helps, Zoran.