If your firewall is completely open....
add the lines
/sbin/iptables -A INPUT -p tcp --dport 25 -j LOG
/sbin/iptables -A INPUT -p tcp --dport 26 -j LOG

On your linux box, open a command window (as root) and type
tail -f /var/log/messages

From an external machine, telnet to port 26.
----- What do you see on your linux box?
From the external machine, telnet to port 25.
----- What do you see on your linux box?

Your issue sounds like the one I was having until I found out my ISP really did block port 25 even though they told me that I was allowed to "run servers" - apparently 'tech support' is a misnomer.

that command was really helfiul (tail -f: A GREAT COMMAND!!! =)) i am defenitly sure that is a serve rproblem. I have called my ISP and they were blocking this port for SPAMMING (!?!??!) .

REALLY THANKS TO ALLL!!

Cheers. Glad we could help.

Hi I don't know if this helps but

I had issues telneting and ssh to my machine from the internet

I has plaing around with hosts.allow and hosts.denly

I basically allowed all hosts connect to all my ports in my machine (i don't think that is safe)

but it worked.

hope that helps.