Tag: Linux

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Getting ready for a 3D printer

I’ve ordered a 3D printer some time ago, and now the time for its arrival is getting nearer and nearer. They might even ship it in the next week or four.

To the the space for the printer, some cleanup is needed. Specifically, I need to replace this:Tyleet ready to be taken down

With this:

New Leetah being installed

I know. It doesn’t look like much of an improvement, but considering that the first one is a Core2 3.0GHz from 8 years ago, and the new one is an I7-6700K from a few months ago, the difference is huge. The footprint of the case will be a lot less, and due to the fans in the old system being as old as they are, the noise level will be considerably less. I do actually intend closing it up once I’ve finished the basic installation and checked that things are working.

What is it:

  • Motherboard: GigaByte Z170 Mini ITX board
  • CPU: Core I7-6700K
  • Ram: 32GB
  • HDD1: M2 NVME 250GB
  • HDD2: 3TB WD Green
  • PSU: Seagate Fanless 520W Platinum
  • OS: Debian Jessie

The one problem I’ve had so far, has been that the power draw was too low. This made the PSU switch off. The solution was to enable dummy load in the BIOS, and now it’s working without problems.

For the curious: In normal operations it’s drawing a whopping 23W. When trying to do a full load with HDD access and full processor load, it’s drawing all of 57W. Much better than the old system that was idling along at 78W and had a top load of 110W. It’s gotten so that the heater in the office now has to switch on now and again, due to the 60W less being pumped out continually.

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Rejecting mails falsely claiming to come from my own domain

For some time now, I’ve been annoyed by spam mail claiming to come from my own domain.

I’m running my own mail server (postfix), so the solution should be simple, right?

I finally took the time to look into it. Using the big manual (google), I found a working solution.

In /etc/postfix/main.cf:

smtpd_sender_restrictions =
        permit_mynetworks,
        permit_sasl_authenticated,
        check_sender_access     pcre:/etc/postfix/check_sender.pcre,
        ...

And then in /etc/postfix/check_sender.pcre I added the following line:

/@mydomain.com$/   REJECT Misuse of local recipient domain.

The system now correctly rejects mail that comes from the outside and tries to send as my own domain.

Thank you to Insyte at serverfault.com for the answer: SMTP-AUTH required for local domains?