Dear All,
My apologize if I post in the wrong place.
I have a very strange problem with my Linux machine that be operated as
Internet Gateway
Below the simple picture of network configuration:
INTERNET ------| Linux |------ LAN / Mail server
Linux machine only runs 2 services: SMTP & HTTP Proxy (webcache).
Problem has started since yesterday of it''s the SMTP traffics (TCP 25)
to
LAN (Eth1). But SMTP traffic to Internet (Eth0) are OK. All other traffic
are OK, run well.
I run telnet the port 25 of internal mail server (from Linux machine), the
response is very slow but success (more than 1 minute). All of email client
Outlook Express, Mac, etc (almost) always get timeout message when trying to
send email through Linux machine.
I run Ethereal to see the packets, seems there is no strange thing.
I let users to relay to ISP''s SMTP server (still NAT by Linux),
traffic
is fine. Email can pass through.
Telnet-ing the port 25 of Linux machine give same response, very slow (but
success). I have tried to pull out all of LAN cable and plug 1 PC directly
to Linux Machine, result is same. I also replaced the Eth1 with another
card, same result
Hope you would share experiences to solve this abnormal problem. What other
tools should I use to detect the problem source?
Thank you so much for your kind help. Your advises are very appreciated.
Thx & Rgds,
Awie
