Hi, I have a SMTP server properly configured with reverse DNS and already listed on OpenSPF. Emails go perfectly to Gmail for example. Problem is : 90% of customer emails to private SMTP servers receive Connection refused instantly, as if the IP is being rejected from not being white listed somewhere. I do mean 90%, so I don't think this is coincidental. I searched for ORBL(back in my day...) but it's been deactivated. So here's the question: What are the places I need to whitelist my SMTP server at so that my corporate mail will go through as legit? What else do I need to do to mark my SMTP as valid and active? Are all these servers querying some unified whitelist or will I need to gain the "confidence"/reputation with EACH of them? Thanks very much in advance for any pointers.
Is the "Connection refused" errors stating anything in your SMTP server log? i.e. "Relay denied"? Looks like your SMTP server is not setup as open relay. Are those users have valid account to login before send?
Hi quad3datwork, the server is closed for relaying unless it matches local domains, I suppose that's the right way? Otherwise I've gotten blacklisted for allowing spam through. The connections are simply refused, like our SMTP server is blacklisted somewhere by IP address...do you know of any such IP blacklist? Anyone else have any pointers? Would be extremely appreciated, thanks in advance.
Even if you are relaying with your own domains, if the person can figure which domains you accept, they can forge your domains. You should look into SMTP AUTH. Try the following site see if your IP is still blacklisted, listed engines are frequently used by a lot of e-mail filters. http://whatismyipaddress.com/staticpages/index.php/is-my-ip-address-blacklisted
Hello, You could use my script as well to see if your MTA is blacklisted or not (Check sig). Regards Thibaut