Email filters gone mad

Just received in my inbox, the following bounce:

Your message

From: Ben Metcalfe

To: [address]

Subj: RE: [backstage] IPs for news feeds?
Sent: 2005-08-17 15:28

has encountered delivery problems to the following recipient(s):

[removed]

Reason: Blocked message
One of the words in the message is blocked.
For security reasons the message was not delivered to the recipient.

Additional info:
The blocked string is: ” XXX ”
The line is: set to 212.58.xxx.xxx (I believe the

All because I was referring to an IP block in the form ‘212.58.xxx.xxx’! How stoopid is that??!?