I have the same problem.

Step 1 -- Works with 127.0.0.1 or localhost
Does not work with actual IP address of the server
(Verizon)

Step 2 -- Works as long as I give the assigned IP address (192.168..)

telnet actualIP 25 -- hangs up. Same with the name

Thanks
--gr
On Fri, 07 Apr 2006 18:09:53 GMT, Greg Hackney <hackney@swbell.net>
wrote:

>justin wrote:
>> hi,
>> I have setup a mail server using postfix. I am behind a router
>> which has its port 25 open. when i send a mail to my server using
>> yahoo. Mailer daemon say cannot establish smtp connection (#4.4.1).
>> Can any one it out its urgent.
>> Thanks.
>> justin....
>
>
>Some basic troubleshooting steps are:
>
>1. Make sure that Postfix is alive and semi-responding:
> From a shell session on the same server that Postfix is running on, type: telnet 127.0.0.1 25
> Make sure you get a welcome banner such as:
> 220 myhostname ESMTP Postfix (2.2.9) ready
> Type in: helo world.com
> Make sure Postfix responded and doesn't hang.
> Type in: quit
>
>2. Make sure that Postfix is listening on your IP address:
>
> Run the command: $ netstat -an | grep :25
> and make sure it's listening on 0.0.0.0 or your IP address, such as:
> tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN
>
> Repeat step #1 above, only using your IP address instead of 127.0.0.1
>
>3. If possible, repeat Step #2 from another system that's on the same network subnet
> as the Postfix server.
>
>4. If possible, repeat step #2 from an system on the Internet (on the other side of your firewall).
>
>5. Repeat step #4 using your system's name, instead of it's IP address.
>
>6. See if your domains records are correct in external DNS by querying another's DNS service:
> host mydomain.com cs.utexas.edu