MTU issue

[cpntblues63]

I keep getting the following error messages in my managed switches:

1 2024-10-29T18:03:44.178-06:00 AUC7K98 CP1 - 0x000e460b - 00000000 GlobalRouter SW WARNING MTU Size Exceeded recvd from xxx.xxx.xxx.xxx, for pkt w/ipSrc = xxx.xxx.xxx.xxx, ipDest = xxx.xxx.xxx.xxx, proto=17 ip_len=1468; requested MTU size = 1427, selected MTU size = 0

where:
- ipSource = my switch
- ipDest = my Cacti server
- recvd from = router/firewall (I've checked with my admin, he says it's not our gear and must be coming from server)

The switches are a pair of clustered 10 Gig managed switches and their MTU setting is 9600 as default for all ports.

It's either a setting in Cacti, or the linux based server itself causing the mtu mismatch so I'm wondering where in Cacti do I set the MTU size?

TIA

[cigamit]

Cacti doesn't set the MTU, thats a function of the networking on the server.

[cpntblues63]

I was afraid of that...

Thanks!

[TheWitness]

Yea, not so much a Cacti issue, more a network configuration issue between the client and the routers in between the clients. You may be trying to use packets that exceed the MTU. Maybe MaxOID's too high for a few devices? Though 1500 bytes is the standard, UDP traffic can present a problem if you set your MaxOID's too high.