I just tried sending an email from my GMail account but I got a response back pretty quick saying that delivery had failed; I was pretty certain the email address was valid.

Looking at the response in greater detail I noticed that it had failed because a relay somewhere along the chain had blocked the message coming from GMail; you can see why here.

Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 16): 550-gmail.com 
is in the AHBL (rhsbl.ahbl.org).  For more info see:
550-http://www.ahbl.org/tools/lookup.php?ip=gmail.com
550 gmail.com - trelane - Google GMail, relaying 
child pornography spam

According to the response that I got, it appears that GMail has somehow got itself on an abusive hosts lists for apparently “relaying child pornography spam”. Strange! Anybody else having this problem?

Whatever happened to “don’t be evil” 🙂