DOKK / manpages / debian 13 / bpftune / bpftune-ip-frag.8.en
BPFTUNE-IP-FRAG(8) System Manager's Manual BPFTUNE-IP-FRAG(8)

BPFTUNE-IP-FRAG - IP fragmentation bpftune plugin for managing fragment reassembly memory limits

For IPv[46] fragmentation reassembly, memory is capped at
net.ipv[46].ip[6]frag_high_thresh


Fragmentation reassembly can fail if this value is set too low; monitor for fragmentation reassembly and bump value if needed.

Avoid bumping it if assembly failures are correlated with increases in frag_high_thresh; this suggests that increasing available memory does not help. While correlation is high, tune down the frag_high_thresh value.

Tunables:

  • net.ipv4.ipfrag_high_thresh: number of bytes devoted to IPv4 fragmentation reassembly; default 4MB
  • net.ipv6.ip6frag_high_thresh: number of bytes devoted to IPv6 fragmentation reassembly; default 4MB



bpf(2), bpftune(8),