[shoutoutuoadi325]

WHY

Fixes #5607.

A proxy reconnecting with remotePort = 0 could reclaim its previous port after another proxy acquired it but before that proxy bound its socket. The successful socket probe let the reconnect overwrite the active allocation.

Check the manager's free-port set before probing the remembered port. If it has already been acquired, use the existing random allocation path. This preserves reuse when the previous port is free and leaves the other proxy's allocation intact.

Tests

• Added a TCP and UDP regression covering reuse, contention before bind, and fallback to a different port. Both subtests fail on current dev and pass with this change.
• go test -race ./server/ports -count=25
• go test -tags noweb ./assets/... ./cmd/... ./client/... ./server/... ./pkg/...
• make build and both existing Alloc Random Port end-to-end specs (legacy and v1)

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[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• server/ports/ports.go
• server/ports/ports_test.go

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_{Reviewed by gpt-6.1-sol · Input: 36 · Output: 2.3K · Cached: 322.8K}