- Check domain accessibility through all gateways via SOCKS5 in parallel
- Resolve domain IPs (v4+v6) and find matches in active route lists
- Distinguish proxy errors (PROXY?) from site blocks (BLOCK)
- Show whois summary (registrar, org, dates, nameservers)
- Add per-entry check button in bypass/direct lists
- Rate-limit: one check at a time (threading.Lock)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>