AOL rejecting mail from IP's w/o reverse DNS ?

Suresh Ramasubramanian suresh at
Wed Dec 3 15:51:02 UTC 2003

Randy Bush  writes on 12/3/2003 10:18 AM:

> you're right.  it will be.  people will have to clean up their
>  or am i missing some reason they can't, other
> than laziness?

Well - unless you have a /24, is typically under the 
control of your upstream provider.

And at least some few upstream providers I have seen over the past few 
years are ignorant of basic DNS principles, and don't know how to do 
proper delegation.

Their sending senior management off on junkets abroad, ostensibly to 
attend APNIC tutorials, seems to be a common cause.  The actual admins 
often remain untrained. Come to think of it, quite a few such ISPs don't 
know to do proper BGP or proper anything else either ...

If that is not the case, and the ISP does know to do reverse DNS, they 
often charge you $$$ for each line they add into their bind configs. 
One of the providers we were looking at (we were shopping for a /24) was 
  charging a rather high sum per line added to their bind configs.

What's more - their support was insisting that the config we sent them 
(just enough to let them delegate authority for the /24 to 
our nameservers) was "wrong".  They apparently were under the impression 
we were going to pay them for each IP in the /24, to add rDNS.

So, especially in countries where most if not all the IP providers you 
get are dumber than rocks, rDNS is often dismissed as an unnecessary 
luxury.  Especially when you have maybe one IP allocated for a colocated 
server, rather than a /24 or two.


srs (postmaster|suresh) // gpg : EDEDEFB9
manager, security and antispam operations

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