[Mimedefang] validating 'possibly forged' helo IP's?

David F. Skoll dfs at roaringpenguin.com
Thu Jan 12 13:15:02 EST 2006


WBrown at e1b.org wrote:

>> 1.  There is only one ptr record per IP.

> Not true. I was testing that on my internal DNS:

Try adding 150 PTR records for a given IP address and watch all hell
break loose. :-)

(The large reply will make the DNS server want to fall back to TCP,
which is blocked by a lot of firewalls whose admins forget (if they
ever knew) that DNS can run over TCP as well as UDP.)

Regards,

David.



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