feat(blog): add systemd-networkd article

content/blog/linux/systemd-networkd.md

@@ -0,0 +1,54 @@
+---
+title: Static addressing with systemd-networkd
+description: Dual IPv4 and IPv6 configuration
+date: 2025-03-04
+tags:
+- systemd
+---
+
+## Introduction
+
+I like to keep up with what established operating systems or Linux distributions
+are doing even though I am not using them all everyday. While trying out
+OpenSUSE again recently, I gave a first try ever to using `systemd-networkd`.
+
+## Configuration
+
+Here is an example of how to configure your network statically with
+`systemd-networkd`. The quirk is that there is no way to specify two `Gateway`
+attributes in a `Network` block. Since you can have multiple `Address` blocks,
+this is an inconsistency that required some reading of the manual before it
+clicked.
+
+Here is what ended up working for my `/etc/systemd/network/20-wired.network`:
+
+``` ini
+[Match]
+MACAddress=fa:16:3e:82:71:b7
+
+[Network]
+Address=37.187.244.19/32
+Address=2001:41d0:401:3100::fd5/64
+DNS=1.1.1.1
+
+[Route]
+Destination=0.0.0.0/0
+Gateway=37.187.244.1
+GatewayOnLink=yes
+Metric=10
+
+[Route]
+Destination=::/0
+Gateway=2001:41d0:401:3100::1
+Metric=10
+```
+
+The `GatewayOnLink` attribute might not be needed for you. I am using it because
+this is an OVH box and this provider likes to reduce instances chatter by
+issuing `/32` netmasks on DHCP. Though I could use a more standard netmask in
+this static configuration, I choose to respect their preference.
+
+## Conclusion
+
+In the end `systemd-networkd` works well and I have no complaints other than
+this quirkiness.