Why do you believe people which are using Level 3 are not aware what it is doing? We have given a very detailed description how it works and also recommendations how to use it. See: http://www.uceprotect.net/en/index.php?m=3&s=5 Additionaly we are writing BIG FAT warnings also into the downloadable zonefile See: http://wget-mirrors.uceprotect.net/rbldnsd-all/dnsbl-3.uceprotect.net gz As you can see we don't make a secret out of what it is: A boycottlist. Therefore we have to assume that those which are using it for blocking do exactly know what they are doing. It clearly depends on where you are and where you expect mail from, if you can or cannot use it for blocking.According to Al Iverson's stats (which didn't get updated since summer 2008) it looks like it is not doing so much false positives if used in North America.See: http://stats.dnsbl.com/uce3 html If used in Germany, Austria or Switzerland it even looks better: See our stats: http://stats.uceprotect.net/week.html Of course it will almost always be necessary to use a whitelist in combination with ASN-Blocking. YMMV Claus von Wolfhausen UCEPROTECT-Network -----Original Message----- From: Raleigh Apple [mailto:rapple at rapidlink.com] Sent: Thursday, May 07, 2009 1:34 PM To: nanog at nanog.org Subject: UCEProtect Level 3 Is anyone else out there aware that the UCEProtect Level 3 email blacklist blocks entire AS? r