Marc Perkel wrote:
Meng Weng Wong wrote:
On Jul 12, 2007, at 9:15 AM, Marc Perkel wrote:
Need a rule written to take advantage of this trick and this could be
a major breakthrough in white listing.
Here's what it needs to do:
1) Take the IP of the connecting host and do an RDNS lookup to get
the name.
2) Verify that the name that was looked up resolves to the same IP
address.
Marc, I'm quite amazed that you still haven't picked up the term FCrDNS!
3) Look up the name in this dns list ===
example.com.hostdomain.junkemailfilter.com
4) if it returns 127.0.0.1 - it's ham
I'd like to suggest that where the domain publishes SPF, we use that;
where it doesn't, we use your algorithm.
I recently coded up a very similar approach; I posted about it on the
SPF and Karmasphere mailing lists. Here is the original message:
SPF is rather useless. Spammers can publish SPF records.
Guess what Marc, spammers can publish ANY DNS records! That includes
TXT records, type 99 (SPF) records, and your precious A and PTR records.
Daryl
