I have a question that has boggled my mind and hopefully someone has come across this issue.
I am running a Cisco 3560 with Version 12.2(50)SE1, and using GRE tunnels to from field sites to the core....I have one of the sites showing the interface MTU to be 9108 bytes, irregardless that I try to change the MTU to 1500 it still shows on the interface as as 9108 bytes:
1#sh int tu1
Tunnel1 is up, line protocol is up
Hardware is Tunnel
Description: Tunnel 1
Internet address is 10.1.1.246/30
MTU 9108 bytes, BW 1500 Kbit, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (5 sec), retries 3
Tunnel source 10.1.1.9, destination 10.1.4.54
Tunnel protocol/transport GRE/IP
Key disabled, sequencing disabled
Checksumming of packets disabled
Tunnel TTL 255, Fast tunneling enabled
Tunnel transport MTU 1476 bytes
On my configuration for the interface:
description Tunnel 1
ip ospf authentication message-digest
ip ospf message-digest-key
ip ospf mtu-ignore
Configuration on the system:
system mtu routing 1500
I have also tried to just have the system mtu 1500, but this does not change on the Tunnel interface.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...