Fedora core 1 sendmail problems

[Homer Sapions]

I have been searching the archives of this list and google and not yet found 
the solution to my problem. It seems like this is a common problem with 
sendmail on new installations of Fedora, so I am frustrated by not finding a 
solution that works for me. I would really appreciate any help.

I had a RedHat 7.3 installation working properly, both sending and receiving 
mail with sendmail. I wanted a clean Fedora install, and since then I can 
send, but not receive mail.

I have modified /etc/mail/sendmail.mc and commented out the line
dnl # DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
then ran make -C /etc/mail and restarted sendmail with service sendmail 
restart.

I also modified /etc/mail/access and added
localhost.localdomain           RELAY
localhost                       RELAY
127.0.0.1                       RELAY
myserver.mydomain.org   RELAY
then restarted sendmail.

I have a 4 port linksys as a router/firewall between my cable modem and my 
server (and 2 other PCs). Port forwarding is enabled on the linksys to allow 
http traffic, and smtp on port 25 to be forwarded to the server - which was 
all working correctly before the Fedora install.

I ran ethereal and watched connections, not that I understand much of the 
packet info. I see connection attempts, but external mail servers never 
complete a connection. The typical pattern seems to be a remote server sends 
a SYN on port 25, I reply with SYN,ACK. Remote sends a SYN, I send 2 
SYN,ACKs. Remote sends a SYN, and I send 3 SYN,ACKs, and eventualy the rmote 
gives up.

>From any PC inside my network I can telnet to the server on port 25 and 
issue basic smtp instructions. I can do the same locally with 127.0.0.1  
e.g.
# telnet myserver.mydomain.org 25
Trying 192.168.1.12...
Connected to myserver.mydomain.org.
Escape character is '^]'.
220 myserver.mydomain.org ESMTP Sendmail 8.12.10/8.12.10; Sun, 28 Mar 2004 
11:41:01 -0500
mail from: someone at xxx.org
250 2.1.0 someone at xxx.org... Sender ok
rcpt to: homer
250 2.1.5 homer... Recipient ok
data
354 Enter mail, end with "." on a line by itself
Subject: test message
this is a test