nftables reload-after-tailscale systemd fix #181

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opened 2026-03-26 23:12:37 +00:00 by forgejo_admin · 2 comments

forgejo_admin commented

2026-03-26 23:12:37 +00:00

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Type

Bug

Lineage

standalone — discovered during Mac agent setup (#174)

Repo

forgejo_admin/pal-e-platform

What Broke

nftables resolves interface names (e.g. iif "tailscale0") to numeric ifindex at load time. If Tailscale restarts and gets a new interface index, the firewall rule silently stops matching — Tailscale traffic gets dropped by the default policy. Discovered when Mac Salt minion couldn't reach the master.

Repro Steps

Reboot archbox (or restart Tailscale)
sudo nft list ruleset | grep iif — shows iif 5 (stale numeric index) instead of iif "tailscale0"
Tailscale traffic (100.x.x.x) is silently dropped

Expected Behavior

After reboot, nftables rules should reference the current Tailscale interface, not a stale index. Firewall should reload automatically after Tailscale starts.

Environment

Host: archbox (Arch Linux)
nftables managed by Salt (salt/states/firewall/)
Tailscale interface: tailscale0 (index varies across restarts)

Acceptance Criteria

After reboot, nft list ruleset | grep iif shows iif "tailscale0" (not a number)
Systemd dependency or timer ensures nftables reloads after tailscaled starts

Notes

Scope clarification: Is this about boot ordering (nftables loads before tailscaled starts) or mid-uptime restart (tailscaled restarts while system is running)? Fix may differ.

Existing salt state at salt/states/firewall/init.sls lines 31-45 already manages nftables rules — verify before duplicating.

feedback_ci_pipeline_lessons — similar nftables boot ordering issue fixed before (PR #81)
pal-e-platform #174 — discovered during Mac agent setup

### Type Bug ### Lineage standalone — discovered during Mac agent setup (#174) ### Repo `forgejo_admin/pal-e-platform` ### What Broke nftables resolves interface names (e.g. `iif "tailscale0"`) to numeric ifindex at load time. If Tailscale restarts and gets a new interface index, the firewall rule silently stops matching — Tailscale traffic gets dropped by the default policy. Discovered when Mac Salt minion couldn't reach the master. ### Repro Steps 1. Reboot archbox (or restart Tailscale) 2. `sudo nft list ruleset | grep iif` — shows `iif 5` (stale numeric index) instead of `iif "tailscale0"` 3. Tailscale traffic (100.x.x.x) is silently dropped ### Expected Behavior After reboot, nftables rules should reference the current Tailscale interface, not a stale index. Firewall should reload automatically after Tailscale starts. ### Environment - Host: archbox (Arch Linux) - nftables managed by Salt (`salt/states/firewall/`) - Tailscale interface: `tailscale0` (index varies across restarts) ### Acceptance Criteria - [ ] After reboot, `nft list ruleset | grep iif` shows `iif "tailscale0"` (not a number) - [ ] Systemd dependency or timer ensures nftables reloads after tailscaled starts ### Notes > **Scope clarification:** Is this about boot ordering (nftables loads before tailscaled starts) or mid-uptime restart (tailscaled restarts while system is running)? Fix may differ. > > Existing salt state at `salt/states/firewall/init.sls` lines 31-45 already manages nftables rules — verify before duplicating. ### Related - `feedback_ci_pipeline_lessons` — similar nftables boot ordering issue fixed before (PR #81) - pal-e-platform #174 — discovered during Mac agent setup

forgejo_admin commented

2026-03-27 21:31:56 +00:00

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Owner

Scope Review: NEEDS_REFINEMENT

Review note: review-400-2026-03-27

Critical finding: The codebase already has a partial fix. salt/states/firewall/init.sls (lines 31-45) creates a systemd drop-in with After=tailscaled.service + Wants=tailscaled.service, ensuring nftables loads after tailscaled at boot. Acceptance criterion #3 ("Salt state manages the systemd drop-in") is already done.

Issues to resolve before moving to next_up:

Clarify the failure scenario: Is this about boot ordering (possibly already fixed) or mid-uptime systemctl restart tailscaled (not fixed by After=)? The After= directive only controls startup ordering -- it does NOT trigger nftables reload when tailscaled restarts.
Update acceptance criteria: Remove criterion #3 (already implemented). Add explicit criterion for the actual delta, e.g.: "After systemctl restart tailscaled, nft list ruleset | grep iif still shows tailscale0."
Specify the fix mechanism: If mid-uptime restart is the scenario, the fix is likely adding PartOf=tailscaled.service to the existing drop-in (causes nftables to restart when tailscaled restarts).
Verify boot scenario first: Reboot archbox and check nft list ruleset | grep iif to confirm whether criterion 1 already passes with existing code.

## Scope Review: NEEDS_REFINEMENT Review note: `review-400-2026-03-27` **Critical finding:** The codebase already has a partial fix. `salt/states/firewall/init.sls` (lines 31-45) creates a systemd drop-in with `After=tailscaled.service` + `Wants=tailscaled.service`, ensuring nftables loads after tailscaled at boot. Acceptance criterion #3 ("Salt state manages the systemd drop-in") is already done. **Issues to resolve before moving to next_up:** - **Clarify the failure scenario**: Is this about boot ordering (possibly already fixed) or mid-uptime `systemctl restart tailscaled` (not fixed by `After=`)? The `After=` directive only controls startup ordering -- it does NOT trigger nftables reload when tailscaled restarts. - **Update acceptance criteria**: Remove criterion #3 (already implemented). Add explicit criterion for the actual delta, e.g.: "After `systemctl restart tailscaled`, `nft list ruleset | grep iif` still shows `tailscale0`." - **Specify the fix mechanism**: If mid-uptime restart is the scenario, the fix is likely adding `PartOf=tailscaled.service` to the existing drop-in (causes nftables to restart when tailscaled restarts). - **Verify boot scenario first**: Reboot archbox and check `nft list ruleset | grep iif` to confirm whether criterion 1 already passes with existing code.

forgejo_admin commented

2026-03-27 22:04:29 +00:00

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Issue body updated per scope review corrections.