What E-Mail Validation Tools Do You Use?

morcego asks: "As we are all too much aware, spam is an increasing problem. Each of us has our own set of tools and methods to try and reduce the amount of spam we receive, each with different pros and cons. Also, on a more broad front, we have options like SPF (+ SRS), Microsoft's own Caller-ID, and Yahoo's DomainKeys that we can use. These days, it is incredibly easy to implement any (or all of these), using publicly available frameworks and libraries (libspf2, and milter, to name a few). I have been using SPF for quite some time now with some measurable results, although nothing earth shattering. Which of these are you using, if any? Why, or why not? Do you think any of them really contribute anything to fight spam?"

Comments

I use GMail :)

[brunes69]

After trying to tune SpamAssassin to work well for months, and being unimpressed by the hit/miss rate, I tok to forwarding all of my incoming email to GMail. I then forward all my email from GMail that is not spam back to my other account :0

I find this way I get 99.95% accuracy - things that GMail misses as spam, my local SpamAssassin catches. As a side bonus I have GMail's awesome interface to read my mail when on the road (much better than the Squirrel Mail I was using, and still better than RoundCube).

This brings up another point - I don't know why Google doesn't add IMAP connectivity to GMail, soyou could use it's interface to read email from other hosts. I don't see why their ad technology would not work with this scheme.

pf OS fingerprinting

[jnieuwen]

I use the OS fingerprinting options from pf to block windows machines from delivering mail on the primary mx. This saves approximately between 300 and 1600 spams a day. Beside that, rejecting mail from hosts without an A record, blacklisting all hosts sending mail to spamtraps with spamikaze, rejecting hosts which falsely claim to be a host in my domain and filtering with bogofilter.