Milter-greylist

Emmanuel Dreyfus <manu@...> writes:

> You didn't understand the problem of MD5 and regex I send amail, rcpt
> <foobarbuz@...> It gets through a MD5 hash:
> ad71c6bc1d51a4be31aaddd7ce5c7ac3
>
> Then you want to match this against /.*@example\.com/ How do you
> immagine that?

Why should I try to match it against a regex ? It would be already in the
list of "greyed" addresses because the match test did occur before.

Something like:

    You send a mail to <foobarbuz@...>


    hash = md5(address)

    greyed = lookup(list, hash)
    
    if (greyed != NULL)
       do things for already seen addresses
    else      
       ok = match(whitelist, address)
       if (ok == NULL)
          install(list, hash, STATE_GREY)
       else
           install(list, hash, STATE_WHITE)
           return accept_message
       endif
    endif

The only reason to match it again would be a change in the config file
that would end in clearing all already stored hashes.

Imho this is what causes a potential problem: can we afford to flush
the whole greyed adresses db upon conf reload because regex were amended ?

This is a trade off between conservative memory usage and greyed db
reconstruction time.

With the hope it clarifies.