UFW VPS Cannot Authenticate TLS Mail

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  Vitruvian Marmot is a music and media production company specializing in making the abstract palatable.

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  The Stereo Bus covers such topics as working with Digital Audio Workstations (DAWs), microphone and instrument combinations, coaching artists to get the most out of their performances, and developing effective business practices for the independent producer.

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  Blab-lab brings fair-trade collaboration, publishing, and legal support to creative works such as music and film.

  (under development)

Today I was setting up UFW in my Ubuntu VPS server and discovered that even with port 993 open I wasn't able to authenticate into my mail.

After some investigation I realized that UFW was blocking local requests to itself! This was a problem because while I was connecting successfully to 993 from outside, the VM was trying to connect to itself to authenticate with the TLS server and database.

The solution was a simple UFW rule:

ufw allow 127.0.0.1

Or, allow me to talk to myself on any port. Works!

I also had to explicitly allow pings for some reason as an after filter to UFW. Otherwise performance was terrible.

In /etc/ufw/after.rules:

-A ufw-after-input -p icmp --icmp-type echo-request -j ACCEPT

© 2010 Dan Connor - All lefts reserved.

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