[CentOS] DKIM

mouss mouss at netoyen.net
Wed Sep 24 20:03:28 UTC 2008


Andrew Norris wrote:
> Back to the PTR RR:
> 
> $ dig +short MX bobhoffman.com
> 10 mail.bobhoffman.com.
>    ^^^^^^^^^^^^^^^^^^^^
> $ dig +short A mail.bobhoffman.com
> 72.35.68.59
> $ dig +short -x 72.35.68.59
> bobhoffman.com.
> ^^^^^^^^^^^^^^^
> 
> mail.bobhoffman.com != bobhoffman.com
> 

so what?
mail.bobhoffman.com is the MX. bobhoffman.com is an RMX.

$ host -t mx yahoo.com
yahoo.com mail is handled by 1 e.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 f.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 g.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 a.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 b.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 c.mx.mail.yahoo.com.
yahoo.com mail is handled by 1 d.mx.mail.yahoo.com.


no one of these is web23004.mail.ird.yahoo.com, ...



> This may not be your main problem, but it certainly isn't helping 
> matters. 

If we ignore the surrounding IPs (too many without rDNS), he has a very 
simple setup, that should not cause any problems.

> Yahoo seems to be pretty picky on reverse DNS.  I had a VPS 
> running a mail server where the PTR matched the host.  I was relegated 
> to yahoo's spam folder until changed from the default PTR which looked 
> mildly like a dialup.
> 

generic PTRs are a different matter.


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