MTU setting 9000 - only ping -l 8980 works

drnicolas · Post by **drnicolas** » 10 Jan 2015 14:20

I changed MTU setting to 9000 and rebooted.

Now, tests with ping -f -l 8972 work; -l 8973 does not work anymore.

Is this a problem ?

Post by **b0ssman** » 12 Jan 2015 06:59

Don't forget about the ip header. It needs a few bytes as well

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drnicolas · Post by **drnicolas** » 12 Jan 2015 08:10

THank you for your answer!

Is the MTU setting 9000 correct or should I enter something like 9014.

Some where else I found that MTU 9000 is actually 9014

Post by **raulfg3** » 12 Jan 2015 08:42

To answer, you must say what is the Max. MTU supported by your NIC ( and the exact ref. to your NIC).

http://n40l.wikia.com/wiki/Base_Hardware_N54L

drnicolas · Post by **drnicolas** » 12 Jan 2015 09:52

NIC is an INtel Gigabit NIC.
The on-board NIC seems to support only 6000

Post by **b0ssman** » 12 Jan 2015 10:12

all the components in the network must support this. even the switch

Lee Sharp · Post by **Lee Sharp** » 12 Jan 2015 22:16

Most things top out at 9000. RealTek and some Broadcoms top out at 6000. Very few managed switches stop at 6000, and most will support 9000. No, you do not want to go "over" 9000.

Onichan · Post by **Onichan** » 13 Jan 2015 01:00

For one if you are using windows to ping then it's ping does NOT include the IP/ICMP overhead, which is 28 bytes. Since 8972 works I'm going to guess you're using windows and your MTU is set to 9000 and working.

Also most Intel NIC's I have seen actually top out at 9014 bytes.

drnicolas · Post by **drnicolas** » 13 Jan 2015 07:35

Okay, then my setting 9000 seems to be right.
Thank you

XigmaNAS