Avoid fragmentation with correct MSS on tunnel interfaces.
Effective MTU and TCP MSS after tunnel encapsulation overheads (IPv4+TCP = 40 bytes).
Effective MTU: 1500 bytes
Recommended TCP MSS: 1460
Overhead: 0 bytes
interface Tunnel0 ip mtu 1500 ip tcp adjust-mss 1460 ! Effective MTU 1500 bytes (base 1500 − 0 overhead) ! TCP MSS = 1500 − 40 (IPv4+TCP headers)
MTU & MSS Tunnel Calculator helps you avoid fragmentation with correct mss on tunnel interfaces. It is commonly used by network admins, IT support teams, ops engineers for tcp mss calculator, ip mtu gre ipsec, tunnel mtu.
Subtracts encapsulation overhead from base MTU and outputs Cisco ip mtu / tcp adjust-mss commands.