View Full Version : [ubuntu] Setting up/testing a mail server

April 1st, 2010, 07:16 PM
Hi, I just tested my mail server for security. I got only this warning saying: Reverse DNS does not match SMTP Banner.

what does this mean? I have my own server and notice my host name I use my domain name but at the end before the .com I see my ISP'S name.

For example instead of having a hostname like domain.com.

I have something like this: domain.ISP.com

How do I change this? I manually deleted the .ISP part but still my ISP name automatically gets attached.

Also is there any good tutorial on teaching how to setup postfix with mysql?

April 1st, 2010, 07:34 PM
You can view your SMTP banner with this command:

echo QUIT|nc 25

To change the hostname for postix:

sudo postconf -e myhostname=mydomain.com
sudo /etc/init.d/postfix restart

April 1st, 2010, 10:57 PM
You also want to make sure that your rDNS matches your A records. If you lack forward confirming reverse DNS, you're likely to get spam-binned most places.