On 2008-04-07 11:54, Phil Snowdon wrote: ...
So why doesn't the forward and reverse match on the Spam emails? Sure the people who look after those ranges should be following the RFCs as well?
Not if they are forging the mail headers, or using extremely short lived domains that only exist for the purpose of spamming.
While I know this isn't going to solve any spam issue (hell i was getting spam from 'correctly' configured dynamic dsl ranges in brasil at the time) and it is informational, but it's more along the lines of letting the world know that a competent admin is in charge of that server and they're doing all they can to be be 'a good internet citizen'
Exactly. Using this to unconditionally reject mail is not good practice, since it isn't standard anyway. Using it to raise the spam score seems reasonable.
much like spf isn't going to stop spam, but it helps to identify whether mail is coming from the right place or not.
SPF is pretty much broken; DKIM is much more likely to be meaningful. But dropping mail (as opposed to marking it as suspect) with any of these techniques carries a real risk of false positives (just like pretty much any black list mechanism). Content filtering has a much better chance.
just to be clear - we are not currently blocking _anyone_ with no reverse PTR or non-matching PTR/Forwards. It just would be nice to be able to reject up front in the SMTP conversation with a simple test rather than going through the full AV/Anti-spam weighting system,
Sorry, but I don't see any way round that. Brian
This was just my monday morning rant since nznog has been quiet for a while, but it's generated some interest.
There's just such an issue with the volume of spam at the moment, that if we started making information stuff mandatory i think it would make things a lot easier to manage. Much like a having a driving test before you take a car on the pulic roads, maybe there should be some sort of test before you can put a host on the internet.
Phil
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