Ola, amigo / Hi, friend!
Thank you for interest!
SPFBL uses standard 127.0.0.2 result code, just like SpamCop. Im pretty sure you can add any DNSBL in Smartermail, no? It's just a matter of adding the host dnsbl.spfbl.net.
Its also possible to use it inside spamassassin, see www.spfbl.net/dnsbl/index.html
and probably smartermail also lets you add it as a filter/rule to mark as spam instead of rejecting.
We also have a greylist for checking URLs in emails, via Spamassassin. See www.spfbl.net/dnsbl/greylist.html
- SPFBL Team