reverse DNS question
Posted on 2008-10-21
I have installed a Barracuda spam firewall to filter all of my *outbound* email from my mail server. Because of this, I now have a DNS question.
The public ip address of my email server is 126.96.36.199 and that is associoated with mail.mydomain.com
All outbound email goes from the mail server first to the Barracuda & then out to the internet. When the Barracuda sends out the mail, the email is identified as coming from 188.8.131.52
Some email messages have been rejected because some recipient's servers attempt a reverse dns lookup on 184.108.40.206 & there is no reverse dns lookup for that ip.
I'm guessing a solution would be to add a "reverse DNS" entry for 220.127.116.11 - mail.mydomain.com
However, I'm worried - I don't want any mail to be sent back to 18.104.22.168 since that is an outbound device only. I want mail to only come in on 22.214.171.124
Is adding this reverse DNS entry safe?