Hi all,

My Linux is Red Hat Linux 7.2.

Now, I have a problems... it is very trouble for me, it is the SMTP service is not work ...

My Linux is setting a firewall, but I setting let the SMTP, HTTP, SSH, FTP to across the firewall....

When I enter "nmap 205.120.55.156"
It show the SSH, HTTP, POP3 port are opened, but haven't see the SMTP port are open...

My sendmail is settied will run after each time boot up...

Can anyone let me know how to open the SMTP port?

Else now my mail server just can send e-mail to outside, but outside like YAHOO, EXCITE.com can't send any e-mail to our server's user to recevied the e-mail

Thanks.

Your best option is to setup ipchains to open port 25 from my understanding. I've never messed with setting up a mail server personally so I couldn't tell you how exactly how to do it. But from what I have read or seen so far, ipchains or setting up your firewall rules is the best way I would presume.

Try reading some of the howto's and the ipchains howto here: http://www.tldp.org/HOWTO/IPCHAINS-HOWTO.html

Look in /etc/mail/sendmail.mc for "DAEMON_OPTIONS", the "Addr" part, meaning the interface it listens on.
Don't forget to rebuild /etc/sendmail.cf and restart sendmail after you change it.

dnl This changes sendmail to only listen on the loopback device 127.0.0.1
dnl and not on any other network devices. Comment this out if you want
dnl to accept email over the network.
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
dnl NOTE: binding both IPv4 and IPv6 daemon to the same port requires
dnl a kernel patch
dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')
dnl We strongly recommend to comment this one out if you want to protect
dnl yourself from spam. However, the laptop and users on computers that do
dnl not have 24x7 DNS do need this.



The questions is do I need add this code to it then the sendmail then will open the SMTP port to received the outside's e-mail?

DAEMON_OPTIONS(`Port=smtp,Addr=205.120.55.156, Name=MTA')