Description | This article describes that Switch-interface MTU is modified to match the interface with lowest MTU when it is added as a member. |
Scope | FortiGate. |
Solution |
- This behavior is by design as when adding a member into bridge (system.switch-interface). Switch-interface (bridge) MTU will be updated to the lowest MTU among members.
Software switch name 'LAN' is configured with member interface 'lan3'. In this scenario, Both (lan3 and LAN) have default MTU of 1500.
# config system switch-interface
lan3 Link encap:Ethernet HWaddr 04:D5:90:EE:82:31
LAN Link encap:Ethernet HWaddr 04:D5:90:EE:82:31
FGT40F-4 # show system switch-interface
lan2 Link encap:Ethernet HWaddr 04:D5:90:EE:82:30
lan3 Link encap:Ethernet HWaddr 04:D5:90:EE:82:31
LAN Link encap:Ethernet HWaddr 04:D5:90:EE:82:30 |
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.
Copyright 2025 Fortinet, Inc. All Rights Reserved.