what am I missing, getting SMTP to work

I am configuring a new machine and I can't get it to work. I am using Core1, all the patches and Postfix. I am trying to use my Linux box as a outgoing mail server from home and not use my ISP's SMTP, I can send mail from the Linux machine but not from my home machines (another Linux for me and Windows for my wife and daughter).

the output of nmap is (From work to home not the same net) says smtp is Closed but I cant figure out why:
PORT STATE SERVICE
21/tcp open ftp
22/tcp open ssh
25/tcp closed smtp
80/tcp open http

my iptables looks like this
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:smtp
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:http
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ftp
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
REJECT all -- anywhere anywhere reject-with icmp-host-prohibi

I am using postfix and ps output says
root 1735 0.0 0.4 7140 620 ? S Apr14 0:00 sendmail: accepting connections
smmsp 1744 0.0 0.3 7316 412 ? S Apr14 0:00 sendmail: Queue runner@01:00:00 for /var/spool/clientmqueue

I am guessing my problem is smtp being closed according to nmap. I did not install telnetd. On the linux machine, I can do telnet localhost 25 and get into mail but I can not do telnet external_ip 25 gives me a connection refused as well as from the Windows machines.

Those of you who are regulars on this list know I am a newbie but I have looked everywhere I can think of and even purchased "Postfix, the definitive guide" with no luck.

This is the killer for me, I even did "service iptables stop" and it still did not work with the firewall turned off. I am not sure where to look now. At my work machine as was suggested by someone here on this list, I installed shorewall and I was going to do that here at home but since iptables stop didnt help, I dont think shorewall would help either.

My configuration by the way is that the linux box is behind a Linksys router so the machine has a 192.168.1.30 address and is on my network. I have tried removing the Linksys and putting the Linux box directly on the net and on the linksys with the Linux IP in the DMZ and also just forwarding the ports...all 3 configurations gave the same result, port 25 closed.

	mike

~~~~~ I'd rather be sailing and  ~~~ .oooO  Oooo.  ~~~~~~~~~~~
Mike Rambour                                   (    )  (     )    
Bug Writer er...Programmer                \   )   (   / 
      mikey@xxxxxxxxxxxxx                  \_)  (_/  
**********************************************************************
If you want to learn more about the ULTIMATE BRITISH sports car,
then take a look at   http://www.singercars.com/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~