The Spamhaus Exploits Block List (XBL) is a realtime database of IP addresses of hijacked PCs infected by illegal 3rd party exploits, including open proxies (HTTP, socks, AnalogX, wingate, etc), worms/viruses with built-in spam engines, and other types of trojan-horse exploits.

If your IP address is listed by the XBL, see the XBL FAQs for solutions

XBL Usage

The Exploits Block List can be used by all modern mail servers, by setting your mail server's anti-spam DNSBL feature (sometimes called "Blocklist DNS Servers" or "RBL servers") to query xbl.spamhaus.org. XBL is also part of a combined DNSBL comprising SBL, XBL and PBL, see: ZEN

Use of the Spamhaus DNSBLs is free of charge for low-volume non-commercial use. To check if you qualify for free use, please see: Spamhaus DNSBL usage criteria.