On 2012-08-09 at 22:04 -0400, Chris Knadle wrote:
> Realistically I'd like to find a way to implement "whole server whitelisting" 
> which was brought up on this list recently.  i.e. when an email is correctly 
> retried, a whitelist entry is made for that server or that source IP address. 
>  
> Because for instance it's silly to greylist all of GMail, and doing so is 
> just 
> a waste of resources on both sides -- and same with any other legitimate mail 
> server.

I encourage folks to take a look at two DNSxL whitelists:

  * list.dnswl.org
    -- the original one (AFAIK), fairly open
  * swl.spamhaus.org
    -- came out in 2010, invitation only presence, major players only

GMail's mailservers tend to make it into list.dnswl.org, I believe just
by community action, not through participation on Google's part (and
you're better off tracking reputation for Google's servers per-IP if
you're worried about the spam which does make it out).

Myself, I use something like:

  accept  !condition = WHITELIST_CACHE_LOOKUP
          !dnslists = list.dnswl.org : swl.spamhaus.org
          dnslists = zen.spamhaus.org
          message = ....

where WHITELIST_CACHE_LOOKUP is an sqlite3 lookup against a DB populated
from server logs, so that known good senders stay whitelisted.  (If
someone is actively whitelisted, that goes away much more rarely than a
temporary blacklist presence, rapidly fixed, so I aggressively cache,
since these lookups are in-path for much else).

That same !condition,!dnslists precedes a couple of other checks too, so
as to bypass things like greylisting.

-Phil

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