tcpdump docker traffic

Tiny howto, so don’t need to look this up as often. In order to tcpdump your own docker traffic, you will need to identify the appropriate interface first:

# docker network ls
NETWORK ID      NAME                      DRIVER              SCOPE
15a300de        bridge                    bridge              local
88d8d7d1        nextcloud_default         bridge              local

From that, we get the network ID. This will be included (at least partly) in the interface name, so we’ll just take the first few characters and grep:

# ip addr | grep 88d8b
9: br-88d8d7d1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default

this gives us the full interface name (ok, basically this is just “br-” followed by the network ID).

We can then just use tcpdump any way we like:

tcpdump -i br-88d8d7d1

Windows/MacOS/Linux Cheatsheet

Für Terminal-Einsteiger. Mit Terminal-Grundlagen, Node.JS und Git.

Cheatsheet CLI as PDF

OAuth2 with Nextcloud (Provider) and GitLab (Client)

I recently configured GitLab as a OAuth2 client to a Nextcloud Instance. I wanted OAuth2 to be the only way of logging in, and Nextcloud to provide the information needed for one-click user signup (actually, three clicks). This process was not entirely straightforward, especially since I don’t want my buttons to read “OAuth2-Generic”. Changing the name after setting everything up, means changing URLs and in combination with Nextcloud this means recreating your tokens. Long story short: I wrote down how I did it.

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Hörenswerte Podcast-Episoden II


Außerdem die Empfehlung sich Ologies (englisch) mal anzuhören.

Hörenswerte Podcast-Episoden

Ich höre einen Haufen Podcasts. Immer mal sind dazwischen außergewöhnliche Episoden. In den letzten Tagen waren außergewöhnlich viele Gute dabei:


Claudius Coenen is a tech-enthusiast. He's writing on all kinds of topics, including programming, technology, gadgets and media.

This site features his occasional articles, findings, documentations.



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