Tailscale re-authentication after key expiry removes all tags (keep them)

Fix Tailscale tags disappearing after key expiry re-authentication

TL;DR: Logging back in as a user makes the node user-owned, which drops its tags. Re-authenticate with a tagged auth key or tailscale up --tags=tag:example instead, and the tags survive.

The error

After key expiration, reauthentication removes all tags from the machine

Symptom level: the device was tag:server, you re-logged it in after expiry, and now ACL rules for tag:server no longer match it.

Fix it

1. Confirm the tags are actually gone

Check the machine in the admin console. If the tags column is empty where it used to list tags, this is your bug.

2. Re-authenticate with tags attached

Option A, auth key with tags baked in (best for servers): generate an auth key that carries the tags, then pass it as the flag value:

sudo tailscale up --auth-key YOUR_KEY_HERE

Replace YOURKEYHERE with the real key value.

Option B, pass tags directly:

sudo tailscale up --tags=tag:server

Expected: the machine reappears in the admin console WITH its tags.

3. Verify ACLs match again

Test the access the tags are supposed to grant (SSH, subnet, port).

Expected: tag-based rules work as before.

When this applies

• Tags vanished right after re-authenticating an expired node
• You logged in interactively as a user (browser flow)
• macOS/iOS forced re-auth is a common trigger

When it does not apply

• Tags were never assigned (first-enrollment problem)
• ACL rules never matched even with tags present (rule problem)
• You want user-owned nodes (then tag loss is expected behavior)

Tool compatibility

All Tailscale clients. Tagged auth keys need an admin/owner to create them.

Variant phrasings

iOS forced re-authentication, then could not connect to anything

Same cause: the re-auth dropped the tags, so tag-scoped ACLs stopped matching. Re-tag and re-auth with the key.

Why it happens

Tags live on the node identity created at auth time. Interactive user login creates a user-owned node with no tags. Only key-based auth (tagged key or --tags) stamps tags onto the new identity.

Edge cases

• Expiry is the trigger, not the bug: with 24h key expiry policies this bites constantly. Automate re-auth with tagged keys instead of clicking through logins.
• Disable expiry as a stopgap: several reporters just disabled key expiry on affected devices to stop the cycle. That trades security for convenience; tagged-key automation is the better fix.
• Key reuse: make the auth key reusable if many machines share the tag set, or one-use per machine for tighter control.