Real-life Operation Vs In-Lab test

htm · 03-25-2004, 06:36 AM

Folks,

Finally I set up IMAP and SMTP services on my REdhat 9.0 server,
I am confused with the following phenomena:

1. IMAP is running fine, I can both telnet at 143 port on the server, and doing an nmap, 143 is also open; but I could not telnet at 143 port from outside, why?

2. I use sendmail, sendmail is running, but doing an namp, I don't see 25 port
is open; also even on the server, I tel net 25 port, connection refused, I am sure
I opened SMTP port when I customize my firewall

Any idea?

Thx,
HTM

david_ross · 03-28-2004, 09:41 AM

Where are you testing from?

Outside your network?

Perhaps your ISP is blocking the ports.

You can see what ports are listening and the services using them with:
netstat -nlp

To check your firewall rules:
iptables -nL

htm · 03-28-2004, 08:50 PM

Sir,

I did a netstat -nlp,

I found my real IP adress's port 143 is listening, that is a good news,
now I also want to have my real IP address's port 25 listening, unfortunately I only
found tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1758/
so how can I make it happen?

Now, I use Redhat 9.0 GUI's firewall rule seeting, I
use Advanced with only the following ports opened:
http and SMTP, will that be enough? I did nopt set both eth0 and eth1 as
trusted devices, is that a problem?

THx,
HTM

david_ross · 03-29-2004, 12:01 PM

You will need to allow access to port 143 if you wnat users to get IMAP access.

As for stopping your SMTP server from listening only on hte loopback it will depend on what server you are using. I am guessing it is sendmail. Look at "/etc/mail/sendmail.mc" and "dnl" the line that contains "127.0.0.1". Then remake your config files:
make -c /etc/mail

And restart sendmail:
service sendmail restart

jsokko · 03-29-2004, 12:53 PM

don't forget to change your hardware router settings to allow access (if you are using one).

htm · 03-31-2004, 12:01 AM

at local server, testing IMAP with 143 port is fine, but telent from
abother machine remotely connection was refused, why?
My IP rule is using advanced, with only http and SMTP ports open
in Redhat's GUI firewall configuration menu?

Thx,
Ed

htm · 03-31-2004, 12:20 AM

There is no impact, I stll cannot twel net teh 25 port even at local
server, connection refused.

Thx,
HTM