Path MTU Discovery
The Firewall Threat Defense device supports Path MTU Discovery (as defined in RFC 1191), which lets all devices in a network path between two hosts coordinate the MTU so they can standardize on the lowest MTU in the path.
This is a placeholder for Help text related to using the Security Help Center seach feature.
Log In to the Cisco Security Documentation Portal
Interfaces and Device Settings Regular Firewall Interfaces Configure Advanced Interface Settings About Advanced Interface Configuration About the MTU Path MTU Discovery
Last updated: Jul 29, 2025
The Firewall Threat Defense device supports Path MTU Discovery (as defined in RFC 1191), which lets all devices in a network path between two hosts coordinate the MTU so they can standardize on the lowest MTU in the path.