UPDATE: Please disregard all that is below (I was talking out my arse). All was good for some time and then I began getting this error again. After some extensive google searching, I found a lot of articles that indicated that using localhost.localdomain for host would cause the mail to be rejected. I changed my hosts file (keeping localhost.localdomain localhost of course) and rebooted. Still didn’t have much luck so I installed sendmail from scratch again using the following instructions from howtoforge and all was good.
http://www.howtoforge.com/configuring-sendmail-to-act-as-a-smarthost-and-to-rewrite-from-address
Again DO NOT USE THE DESTRUCTIONS BELOW
I noticed last week that my emails were not being delivered properly. After taking a look at when the issue started, I realized that it was about the same time I updated my box.
My email was being returned with the reason: 550 Banned rcpt apache@localhost.localdomain. There was also another error 554 5.0.0 Service unavailable. Both of these errors on their own were not to helpful. I asked a friend (the one who sold me the box) to help and he gave me some good advice, but I was unable to resolve the issue and several Google searches didn’t reveal any solution.
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