helenp - 8:37 am on Jan 22, 2012 (gmt 0)

Just checked my error log, had 3 406, all 3 in spamhaus,
the first dont know what is, is chinese, the second is I think an important internet provider, not sure:
Comcast Cable Communications Holdings, Inc
the third is also from comcast cable.

This is spamhaus guidelines for one of blacklisting:
Should I use the PBL to block access to my webserver?
No! A listing in the PBL does not mean there is anything 'wrong' with the IP address or end user. A PBL listing does not mean an address is an open proxy or run by a spammer. All it means is that the IP address has been designated as 'not allowed to make direct-to-MX SMTP connections'. The majority of legitimate connections to webservers come from IPs listed in PBL. Please do not block innocent users.

And this is for the most frecuent one:
Should I use the XBL to block access to my webserver since it means that the IP address has a virus or open proxy?
A listing in the XBL does not mean this. It means that at one time the IP address may have had a virus or open proxy.

The XBL contains mostly dynamic IP addresses, meaning the user you would be blocking is probably not going to be the user with the exploited computer. Please do not block innocent users.

If you still feel you must use the XBL in this way, do not refer users back to Spamhaus. You must deal with blocked users yourself. Either by giving them a point of contact, or perhaps by instituting a CAPTCHA + cookie system to screen out spam-bots.

Maybe this is normal practice in shared hosting, no idea, but I dont think its the correct.

He just closes the door using a 406