Open Letter to Rev: Quality Is Job #1

[Bill Marriott]

> The most common cause for this is when a whole range of IP addresses is 
> blacklisted by one of the various "watchdog" groups on the net. Some 
> places will blacklist an entire range of IP addresses rather than take the 
> time to identify the IP of a single spammer. (Some providers have gone as 
> far as blocking whole countries.) This is completely unfair, but it 
> happens. There is no easy way for the sender (in this case, Runtime) to 
> know where the block is or who initiated it.

Actually that's not true; there are multiple resources to check if your IP 
is listed:

http://www.mxtoolbox.com/blacklists.aspx
http://www.robtex.com/rbls.html
http://www.dnsstuff.com/tools/ip4r.ch?ip=

I know there's more but those are a good start.