Packet fragmentation drops indicate MTU misconfiguration

Packets are being dropped due to IP fragmentation, indicated by the 'fragment' reason label in dropped packet metrics. Tailscale does not support fragmented packets, suggesting MTU size is incorrectly configured on clients or intermediate networks.

Monitor tailscaled_inbound_dropped_packets_total and tailscaled_outbound_dropped_packets_total filtered by reason='fragment'. Reduce MTU size on affected clients or networks. For Tailscale, recommended MTU is typically 1280 for IPv6 compatibility or 1420 for most networks.