So, this week we had an e-mail issue at my company. For one of our clients' domains, any e-mail they tried to send to us was returned marked "undeliverable". After several conversations with our IT company and our clients' IT department, it was discovered that the e-mails were being blocked because our client's IP address was on the SORBS blacklist.
The SORBS blacklist was created by an individual (possibly with help from a few others) who appears to have repeated patterns of adding non-infected or secured machines to their blacklist in an effort to extort money out of them. Our client got their IP removed without a donation.
I am unsure whether our IT company set up our mail server to use the SORBS blacklist (as our client claims) or if it is on some server on the mail hop route (as our IT company claims).
Our IT company did install a tool which apparently showed all e-mails that were hitting the server and none of the e-mails from the client showed up, which leads me to believe that it is not on our server but somewhere else.
Any thoughts?
