[CentOS] Mail delivery failing with 450

[John R Pierce]

Kai Schaetzl wrote:
> It's better, but still:
>
> - as the MX is the same as your domain name you do not need an MX
> - as all your hosts point to the same IP you can just use a wildcard
> - as I'm sure you don't change your hosts several times a day you can up 
> the TTL to a more reasonable time like 86400 (=a day)
> - having four ns records all point to the same IP is just, uhm, pointless
>   

worse than pointless, its ugly.  in the event your server is down and 
not responding, a lookup server will try it 4 times as many times as it 
otherwise would.

the only NS records that should be in your zone are exactly the same as 
the ones in the registrar for the domain.

$ whois obrien-pifer.com
...
   Domain Name: OBRIEN-PIFER.COM
   Registrar: WILD WEST DOMAINS, INC.
   Whois Server: whois.wildwestdomains.com
   Referral URL: http://www.wildwestdomains.com
   Name Server: NS1.OBRIEN-PIFER.COM
   Name Server: NS2.OBRIEN-PIFER.COM

   Server Name: NS1.OBRIEN-PIFER.COM
   IP Address: 70.62.90.185
   Registrar: WILD WEST DOMAINS, INC.
   Whois Server: whois.wildwestdomains.com
   Referral URL: http://www.wildwestdomains.com


   Server Name: NS2.OBRIEN-PIFER.COM
   IP Address: 70.62.90.185
   Registrar: WILD WEST DOMAINS, INC.
   Whois Server: whois.wildwestdomains.com
   Referral URL: http://www.wildwestdomains.com



I'm surprised the registrar let you register two HOST names for the same 
IP, they aren't supposed to do that.