Base interface MTU
MSS baseline (IP headers)
IPv4
IPv6
Typical TCP MSS uses MTU − 40 (IPv4 20 B + TCP 20 B).
Overlay overhead (bytes)
None (0)
GRE (24)
IPsec (~58, ESP + outer IP approx.)
VXLAN (50)
GENEVE (50)
WireGuard (~80 approx.)
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