Linux DNS timeouts

### What is the issue?

I was trying to reproduce a bug and so I was building from source: https://github.com/tidbyt/pixlet/blob/main/docs/BUILD.md . `make build` called for `go build $(LDFLAGS) $(TAGS) -o $(BINARY) tidbyt.dev/pixlet`

Errors I got in the build process
main.go:6:2: github.com/spf13/cobra@v1.8.0: Get "https://proxy.golang.org/github.com/spf13/cobra/@v/v1.8.0.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/login.go:17:2: github.com/Code-Hex/Neo-cowsay/v2@v2.0.4: Get "https://proxy.golang.org/github.com/%21code-%21hex/%21neo-cowsay/v2/@v/v2.0.4.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/login.go:18:2: github.com/Code-Hex/Neo-cowsay/v2@v2.0.4: Get "https://proxy.golang.org/github.com/%21code-%21hex/%21neo-cowsay/v2/@v/v2.0.4.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/buildifier.go:27:2: github.com/bazelbuild/buildtools@v0.0.0-20230425225026-3dcc8d67e8ea: Get "https://proxy.golang.org/github.com/bazelbuild/buildtools/@v/v0.0.0-20230425225026-3dcc8d67e8ea.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/buildifier.go:28:2: github.com/bazelbuild/buildtools@v0.0.0-20230425225026-3dcc8d67e8ea: Get "https://proxy.golang.org/github.com/bazelbuild/buildtools/@v/v0.0.0-20230425225026-3dcc8d67e8ea.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/buildifier.go:29:2: github.com/bazelbuild/buildtools@v0.0.0-20230425225026-3dcc8d67e8ea: Get "https://proxy.golang.org/github.com/bazelbuild/buildtools/@v/v0.0.0-20230425225026-3dcc8d67e8ea.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/buildifier.go:30:2: github.com/bazelbuild/buildtools@v0.0.0-20230425225026-3dcc8d67e8ea: Get "https://proxy.golang.org/github.com/bazelbuild/buildtools/@v/v0.0.0-20230425225026-3dcc8d67e8ea.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/buildifier.go:31:2: github.com/bazelbuild/buildtools@v0.0.0-20230425225026-3dcc8d67e8ea: Get "https://proxy.golang.org/github.com/bazelbuild/buildtools/@v/v0.0.0-20230425225026-3dcc8d67e8ea.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/check.go:11:2: github.com/fatih/color@v1.16.0: Get "https://proxy.golang.org/github.com/fatih/color/@v/v1.16.0.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
cmd/profile.go:12:2: github.com/google/pprof@v0.0.0-20240424215950-a892ee059fd6: Get "https://proxy.golang.org/github.com/google/pprof/@v/v0.0.0-20240424215950-a892ee059fd6.zip": dial tcp: lookup proxy.golang.org on 100.100.100.100:53: read udp 100.69.107.47:55164->100.100.100.100:53: i/o timeout
....

I was quick to realise that 100.XXX.... was in the wireguard area, I then did `tailscale down`, did `make build` again, and I stopped having these IO Timeout issues.

### Steps to reproduce

1. `git clone git@github.com:tidbyt/pixlet.git`
2. `cd pixlet`
3. `make build`

### Are there any recent changes that introduced the issue?

Not aware.

### OS

Linux

### OS version

ArchLinux

### Tailscale version

1.70.0

### Other software

Make
Git
Go

### Bug report

BUG-5be495f0cadfd55d3d0f5310b561dda841e2c00731a28d41a7cfe97e71b61ce8-20240806191316Z-764528fde0f430b8

Start with docs/BUILD.md and the make build entry point, then reproduce the failure on Linux/ArchLinux with Tailscale 1.70.0 enabled and compare it after tailscale down. Use the proxy.golang.org DNS timeout and the bug report as the observed behavior; done means the cause and an accepted fix or documented limitation are established.

Written by the indexing model from the issue text.