@ S0lo
I did indeed check the rDNS and make sure it was pointing back to the mail server. Good call on that, because that's one of the most important factors to watch for when blacklisted.
I came across the second link you have posted and found that very useful.
@ Alans
I came across an article that discussed the technique you described in the post. It's actually quite a good idea to pinpoint the issue.
Cheers,
ZiPPy
ZiPPy
