That would be a nice addition :) S -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Davide Libenzi Sent: Tuesday, March 30, 2004 2:04 PM To: XMail mailing list Subject: [xmail] Re: DNS and Cached DNS in Xmail
On Tue, 30 Mar 2004, Tracy wrote: > FCrDNS: Take the connecting IP address, retrieve all PTR records > (hopefully only one, but possible to get more). Then take the PTR > record(s) and do A lookup on it. Compare the connecting IP address to > the A records returned - if no match, either the DNS for the > connecting IP has been misconfigured/corrupted, or it's being forged > by a spammer. (Of course, this assumes that RDNS is in place for all > connecting IP addresses - a policy I have implemented for my server > anyway.) > > RCfDNS: Take the HELO/HELO name, retrieve all A records. Starting with > the first returned A record, do PTR lookup. If HELO/EHLO matched PTR > found for any A record, assume valid, otherwise reject as > misconfigured/corrupt DNS or forgery. > > The RCfDNS is going to be expensive, due to the possible number of > lookups and the string comparisons,so it may not be worth the expense. > However the FCrDNS I definitely want to implement. > > I don't know if you would be interested in this kind of code or not > for inclusion in a future version - if so (and you can stand my poor > coding skills :) I'd be happy to share once I have something working... Nope. But I was thinking that XMail could have a special filter call right before sending the response to the DATA command. A file with all the info (IPs, sender, recipients, etc..) will be passed to the filter, that in turn can reject by returning certain error codes. So this stuff can be done with filters. How do you like it? - Davide - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED] -- Binary/unsupported file stripped by Ecartis -- -- Type: application/x-pkcs7-signature -- File: smime.p7s - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
