Archive for 2015

Analysing performance problems with systemd

Now that Systemd is the default init-system in fresh installations of Debian GNU/Linux it is worth highlighting some of the new features.

Validating SPF and DKIM at SMTP-time with exim

In our recent articles we've discussed creating SPF-records to avoid spoofed mails, and the creation and setup for DKIM-signing emails, for a similar purpose. Here we'll look at the other side of the coin; performing DKIM and SPF testing on your incoming email.

Tying together SPF and DKIM with DMARC

When it comes to increasing deliverabiity of email, and preventing spoofed/forged emails the preferred solution these days is DMARC, which allows the use of SPF and DKIM to be enforced for domains in a unified manner.

Avoiding mail-spoofing with SPF

The Sender Policy Framework, or SPF, is an email-validation system which is designed to allow spoofed mails to be indentified. In this brief introduction we'll look at how you can configure your outgoing emails to take advantage of this validation.

DKIM-signing outgoing mail with exim4

There have been several systems designed to prevent mail spoofing over the years, the two most prominent solutions are DKIM and SPF. Here we're going to document the setup of using DKIM to signing outgoing mails with Debian's default mail transfer agent, exim4.

Setting up a personal secure apt repository

Packages under development aren't always ready to be in the main Debian archive. But that doesn't mean it should be hard for people to install them. When asking people to test programs, it is most convenient to present it in the

Preventing SPAM connections with bird.

Bird is an Internet routing daemon with full support for all the major routing protocols. It allows you to configure hosts to share routing information, via protocols such as BGP, OSPF, or even statically. Here we're going to look at using it to automatically blacklist traffic from SPAM-sources.

Using the rubocop ruby code and style analyzer

If you're developing code that you expect others to read and work with then it is very important to pick a consistent style, and having a style-checker can make enforcing your choice much less painful. Here we'll take a look at the rubocop analyzer for Ruby.

Easily working with multiple repositories (git, hg, etc)

There are situations where it is ueful to checkout multiple repositories, which might use different revision control systems, and operate upon them as a group. This is what the mr tool was designed for.

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