Fixed

• NetBSD UDP probes: Auto-detect source IP for UDP DGRAM sockets on NetBSD. Fixes "No route to host" (EHOSTUNREACH) when sending UDP probes without --source-ip (#47)
• NetBSD IPv4 PMTUD retry spam: PMTUD now terminates immediately on first DF flag failure instead of retrying every probe round. Prints a single warning when IP_DONTFRAG is unavailable (#47)

Full Changelog: https://github.com/lance0/ttl/compare/v0.18.1...v0.18.2