white list and mailing lists (eg. Yahoo groups)

Vernon Schryver vjs@calcite.rhyolite.com
Mon Feb 4 19:38:58 UTC 2002


> From: Levent Serinol <lserinol@yahoo.com>

> ...
>   My problem is about huge mailing lists, like Yahoo
> groups. How can I able to filter these groups to not
> threat them as spam ? White listing IP looks like bad
> idea 'cause they have many IP addresses. 
> Is there any way I can do this kind of filtering ?
> one more question about IP addresses. Can I put a IP
> block or  subnet for white listing ?

As the dcc man page in the DCC source or at 
http://www.rhyolite.com/anti-spam/dcc/dcc-tree/dcc.html#X-DCC Headers
says, you can include white or blacklist entries like

  ok     IP    10.1.2.0/24

However, that is really a short hand for the obvious equivalent like
 
  ok     IP    10.1.2.0
  ok     IP    10.1.2.1
  ok     IP    10.1.2.2
  ...
  ok     IP    10.1.2.255

and could produce a very large whitelist.

Another problem with "OK" whitelisting by IP address is that it
white-lists all mail from the source.  Yahoo "groups" mailing lists
have been abused in the past.

If possible, it is better to white-list using other characteristics of
the mailing list, including its envelope Mail_From or header From: value.


It is possible to use "OK2" white-listing.  Consider this example:

  ok2    IP        10.1.2.2
  ok2    env_from  list@domain.com

That example would white-list only mail that both comes from the SMTP
client at 10.1.2.2 and carries the envelope Mail_From value list@domain.com



Vernon Schryver    vjs@rhyolite.com



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