Exchange mail flow not working? Check your (Cisco) firewall!

Reading Time: < 1 minute I’ve come across this issue several times: External mail (or mail between Exchange servers) cannot be delivered, however when you check with telnet the Exchange server(s) are responding. When you check via telnet on the external IP you get something similar: In this case it was a Cisco ASA firewall that had (E)SMTP filtering feature (also called Mailguard) enabled, which is the default setting. Unfortunately, this feature filters very strict and blocks extended commands that are allowed by RFC5321 which

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I am now an Exchange MVP!

Reading Time: 2 minutes For those who weren’t following me on Twitter (or Facebook or whatever), today I received an important mail: Dear Dave Stork, Congratulations! We are pleased to present you with the 2014 Microsoft® MVP Award! This award is given to exceptional technical community leaders who actively share their high quality, real world expertise with others. We appreciate your outstanding contributions in Exchange Server technical communities during the past year. After checking headers for spoofing etc. (hey! It’s my expertise after all

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