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fix(ringtail): explicitly enable net.ipv4.ip_forward

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After the static IP change, k3s/flannel pod networking broke because
ip_forward was 0. NixOS doesn't enable IP forwarding by default — it
was previously being set implicitly somewhere in the NM-managed /
scripted-DHCP path. With static networking we have to set it ourselves.

Verified at runtime via sysctl -w before adding here; pod outbound
came back immediately and Tailscale VIP services recovered without
any pod restarts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erich Blume 2026-05-12 09:51:16 -07:00
commit a4a30aad44
2 changed files with 7 additions and 1 deletions
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2
docs/changelog.d/ringtail-static-ip.infra.md
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@ -1 +1 @@
Pin ringtail's wired IP to `192.168.1.21` via NixOS scripted networking; NetworkManager no longer manages `enp5s0`. Removes DHCP lease renewal as a failure mode after a silent lease teardown took ringtail offline.
Pin ringtail's wired IP to `192.168.1.21` via NixOS scripted networking; NetworkManager no longer manages `enp5s0`. Removes DHCP lease renewal as a failure mode after a silent lease teardown took ringtail offline. Also explicitly enables `net.ipv4.ip_forward` (previously set implicitly by scripted-DHCP) so k3s pod networking and Tailscale routing continue to work with static networking.

6
nixos/ringtail/configuration.nix
View file

@ -31,6 +31,12 @@ in
networking.defaultGateway = "192.168.1.1";
networking.nameservers = [ "192.168.1.1" "1.1.1.1" ];
# K3s pod networking and Tailscale tunnel routing require IP forwarding.
# NixOS leaves this off by default; previously it was being enabled
# implicitly by NM/scripted-DHCP setup, but with static networking we
# have to set it explicitly.
boot.kernel.sysctl."net.ipv4.ip_forward" = 1;
# Time zone
time.timeZone = "America/Los_Angeles";