Blacklist Monitoring

SBL, CSS, XBL, and PBL each say something different about your IP. The Spamhaus return code is the diagnosis. Here is how to read it and who has to file the removal.

Blacklists score two things: the IP a message came from and the domains inside it. Confuse them and you fix the wrong problem when mail starts bouncing.

Organizations adding IPv6 to their email infrastructure often don't realize that IPv6 addresses start with zero reputation, that blacklisting works differently, and that many monitoring setups only check IPv4.

Even legitimate email senders can end up blacklisted. Understanding what triggers a listing is the first step to staying off the lists.

Getting blacklisted happens. Before you request delisting, follow these steps to avoid making the situation worse.

Cloud hosting providers face unique blacklist monitoring challenges: large IP pools, frequent IP reuse, and the need to monitor only active resources.

Getting listed on a blacklist isn't uncommon. Here's how it happens, what the consequences are, and why fast detection matters.

In Part 1 we covered what blacklists are and how they're built. Here we look at how mail administrators use them to filter inbound spam.

Real-time Blackhole Lists (RBLs) are a simple way for organizations to share locations of email systems known to send spam. Here's how they're built.