Dnswl.org Recommendations

So I just had myself added to the dnswl.org whitelist and I got this email from their administrator.

Does he/she make a good point? Is it fixable, or does it even need to be fixed?

(IP address chaged to xx and domain changed to domain)


Completely beyond the scope of DNSWL though - but as the kind person I am
(usually), you’ll get a few suggestions:

While looking around, I spotted this:

$ host ns1.box.domain.com
ns1.box.domain.com has address xxx.xxx.xx.xxx
ns1.box.domain.com has IPv6 address xxxx:xxxx:x:xx:xxx:8001

$ host ns2.box.domain.com
ns2.box.domain.com has address xxx.xxx.xx.xxx
ns2.box.domain.com has IPv6 address xxxx:xxxx:x:xx:xxx:8001

… That is a serious mistake. There is a reason >at least< two DNS servers are


$ telnet xxx.xxx.xx.xxx 25
Trying xxx.xxx.xx.xxx…
Connected to xxx.xxx.xx.xxx.
Escape character is ‘^]’.
220 box.domain.com ESMTP Hi, I’m a Mail-in-a-Box (Ubuntu/Postfix; see

As your mail server tells everyone “Hi. My name is box.domain.com”, you
should also consider using that host name as a PTR<->A for your FcRDNS.

All that being said, you have been listed under the DNSWL ID #41867.

Kind regards,
John Smith

In 15 years of running my own mail server I have (almost) never had two nameservers. I don’t know what he’s thinking.

you should also consider using that host name as a PTR<->A for your FcRDNS

That’s true, but you should have that working already or the status checks would be telling you reverse dns isn’t set up.

(I’m concerned I may sound a little snarky there. Not intended.)

Hey @JoshData,

I think I’ll go with your expertise here.

Also, I did notice that a couple of weeks ago, I received a status email saying my reverse DNS does not resolve to my IP, but then without my even making any changes the issue seemed to be resolved. I don’t see any warnings on the status page. Not sure what’s going on there.

It’s probably just a temporary network glitch. I get that too from time to time.