DNS MX Problem
My DNS server is slackware kernel 2.4.29, running named BIND 9.2.3 ( I am also in the process of updating the system)
I may be having a problem with my DNS setting. Recently we had some "Experts" in reconfiguring our DNS they had sold us some hardware firewalls.
My mail is now getting blocklisted, and the only major change was the DNS setting.
The info I am not writing the complete named file, only those that involve the MX part.
IN MX 10 mail.mydomainname.net
ns2 IN A 20#.##.#.#8
mail IN A 20#.##.#.1#7
sloppyjoe IN A 20#.##.#.#8
barracuda IN A 20#.##.#.1#7
Sloppyjoe is my actual mail server, which is also my backup DNS server.
Barracuda is a barracuda spam firewall. Mail comes in addressed to firstname.lastname@example.org go to the Barracuda then to sloppyjoe. The problem happens when a bot from a blocklist runs an MX lookup. It says that it should be barracuda.mydomainname.net NOT mail.tusculum.edu.
Prior to this change the mail.mydomainnname.net pointed to sloppyjoe.
If I put mail.mydomainname.net in an internet browser address bar, I get sloppyjoe which is running Squirrelmail. I have to access the barracuda via barracuda.tusculum.edu.
None of this seems right. In the first line, should I change mail to barracuda? Am I missing something?
If you need more info let me know.
In general, you should use cname entries to manage virtual names for email, web, etc., but...
You should make;
mailgate.yourdomain point to your firewall's fqdn by a cname
firewall.yourdomain should forward ports (25, maybe 110, 998, etc.) to your real mailserver inside your lan or in your DMZ.
Make your main MX record point to your mailgate name.
Then it's just a matter of making sure your mail server is configured right for its environment.