tailscale/health
Anton Tolchanov 8cc5c51888 health: warn about reverse path filtering and exit nodes
When reverse path filtering is in strict mode on Linux, using an exit
node blocks all network connectivity. This change adds a warning about
this to `tailscale status` and the logs.

Example in `tailscale status`:

```
- not connected to home DERP region 22
- The following issues on your machine will likely make usage of exit nodes impossible: [interface "eth0" has strict reverse-path filtering enabled], please set rp_filter=2 instead of rp_filter=1; see https://github.com/tailscale/tailscale/issues/3310
```

Example in the logs:
```
2024/02/21 21:17:07 health("overall"): error: multiple errors:
	not in map poll
	The following issues on your machine will likely make usage of exit nodes impossible: [interface "eth0" has strict reverse-path filtering enabled], please set rp_filter=2 instead of rp_filter=1; see https://github.com/tailscale/tailscale/issues/3310
```

Updates #3310

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
2024-02-27 00:43:01 +00:00
..
healthmsg health: warn about reverse path filtering and exit nodes 2024-02-27 00:43:01 +00:00
health.go health: warn about reverse path filtering and exit nodes 2024-02-27 00:43:01 +00:00
health_test.go all: use set.Set consistently instead of map[T]struct{} 2023-09-09 10:59:19 -07:00