SpamScan analyzes the IP addresses used by your mail server to send out email messages, and checks them against Relay Blackhole Lists or "RBLs". If your server is listed on an RBL list you may experience issues with emails becoming blocked, returned, or delayed. Below is the current RBL status of the IPs on your server. An "OK" status means that your server's IP addresses are not listed on an RBL.