Arrogant RBL list maintainers

Jon Lewis jlewis at
Wed Dec 9 11:29:54 CST 2009

On Wed, 9 Dec 2009, Mike Lieman wrote:

> Is there an RFC detailing that specific text strings must be used for static
> v. dynamic addresses?

There's this expired draft

But really, the rdns should just clearly indicate the use of the IPs if 
you're going to do generic/script generated rDNS. doesn't tell me anything except that this IP is 
part of a large block of generic rDNS.  Something like at least indicates that the IPs are 
static, while clearly indicates the space 
is dynamic.  Doing this takes much of the guesswork out of it when others 
on the net need to decide "should we accept mail from this IP?"  Keeping 
the indicator as close as possible to the domain helps out for things that 
do simple string matching.  i.e.  with, 
it's a safe bet I don't want mail from *  That's 
easier to block (with a single rule) than

Still, if you're serious about getting mail from that IP 
delivered, its far better to have the PTR = the domain or system name than 
some generic string roughly equivalent to all the neighboring IP PTRs.

  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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