Jeff (and list),
I'm worried that spammers can use SURBL to identify honeypot email
servers by using unique subdomains. A spammer must merely send a unique
subdomain URL to every address on their list, and if that unique
subdomain is blacklisted in SURBL, they have identified a potential
honeypot and will no longer send spam to that address/server.
It is therefore my humble opinion that only the second-to-top domain
name should be listed in SURBL, and not any of the subdomains.
Thoughts?
-Matthew Wilson