[colug-432] Recent change in retry behavior from large e-mail sites, affecting greylisting?

[Joshua Kramer]

On Wed, 12 Jan 2011, Rob Funk wrote:

> They may be using a blocklist that prevents them from receiving mail from IP
> addresses whose Terms Of Service prohibit running mail servers. Many home
> ISPs add their address blocks to such blocklists themselves, and many mail
> servers (including mine) use such lists. Mail coming from residential
> addresses is almost always spam or malware from zombie machines.

What's interesting is, MSN and Hotmail are the *only* providers for which 
this was a problem.  Even Microsoft's Small Business web and e-mail 
service, upon receiving an e-mail from me, sent me a bounce back saying, 
"If you are a real human click on this link and we will whitelist your IP 
address."  (And yeah, I obviously checked the address and the 
corresponding IP address before clicking on the link.  :) )