negative caching of throwaway spam domains
ka at pacific.net
Wed Jun 21 16:51:15 UTC 2006
We have 3 spam filtering machines that each run a bind caching
nameserver to help with rbl lookups, etc..
After mail passes through these machines it goes to our mail hub.
Every so often, a spam from a throwaway spam domain will get through the
spam filtering machines to the mailserver hub. The caching nameserver on
the spam filtering machine will be able to lookup the sender's hostname,
so sendmail accepts it.
But, sendmail, on the mailserver hub will bounce it back to the spam
filtering machine with an error.. 'Domain of sender address
jthlhiyue at halosalbum.com does not exist'. (that one is from this am..
registered yesterday by a spammer).
The question is, is there something I can do to, other than telling the
mail filter machines to all use the same instance of bind to avoid this
Also, a bit off topic, but it occurs to me that this kind of information
is useful in spam fighting. Are there any rbls out there that list all
domains registered in the last 48 hrs?
Thanks for any ideas!
More information about the bind-users