# Dnswl.org Recommendations

**URL:** <https://discourse.mailinabox.email/t/dnswl-org-recommendations/667>\
**Category:** Improvements\
**Created:** [July 14, 2015, 8:03pm UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667 "2015-07-14T20:03:34Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![francoischevel](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/francoischevel/32/181_2.png) [@francoischevel](https://discourse.mailinabox.email/u/francoischevel)\
**Post date:** [July 14, 2015, 8:03pm UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667/1 "2015-07-14T20:03:35Z")

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So I just had myself added to the [dnswl.org](http://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)

> Hi,

> 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](http://ns1.box.domain.com)  
> [ns1.box.domain.com](http://ns1.box.domain.com) has address xxx.xxx.xx.xxx  
> [ns1.box.domain.com](http://ns1.box.domain.com) has IPv6 address xxxx:xxxx:x:xx:xxx:8001

> $ host [ns2.box.domain.com](http://ns2.box.domain.com)  
> [ns2.box.domain.com](http://ns2.box.domain.com) has address xxx.xxx.xx.xxx  
> [ns2.box.domain.com](http://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  
> required.

> Also,

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

> As your mail server tells everyone “Hi. My name is [box.domain.com](http://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

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**Author:** ![JoshData](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/joshdata/32/2153_2.png) [@JoshData](https://discourse.mailinabox.email/u/JoshData)\
**Post date:** [July 14, 2015, 9:07pm UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667/2 "2015-07-14T21:07:39Z")

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> [@francoischevel](#):
>
> … That is a serious mistake. There is a reason \>at least\< two DNS servers are required.

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.

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**Author:** ![JoshData](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/joshdata/32/2153_2.png) [@JoshData](https://discourse.mailinabox.email/u/JoshData)\
**Post date:** [July 14, 2015, 9:08pm UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667/3 "2015-07-14T21:08:09Z")

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

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**Author:** ![francoischevel](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/francoischevel/32/181_2.png) [@francoischevel](https://discourse.mailinabox.email/u/francoischevel)\
**Post date:** [July 14, 2015, 9:47pm UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667/4 "2015-07-14T21:47:40Z")

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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.

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**Author:** ![JoshData](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/joshdata/32/2153_2.png) [@JoshData](https://discourse.mailinabox.email/u/JoshData)\
**Post date:** [July 15, 2015, 11:45am UTC](https://discourse.mailinabox.email/t/dnswl-org-recommendations/667/5 "2015-07-15T11:45:13Z")

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