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Forum Discussion

boneyard's avatar
boneyard
Icon for MVP rankMVP
Jul 17, 2012

F5 setting don't fragment bit

am running into a situation where it appears the F5 is setting the don't fragment bit of a packet that didn't have it set initially. what can be causing this? is there a way to turn this off?  
config
design
Hamish's avatar
Hamish
Icon for Cirrocumulus rankCirrocumulus
Jul 18, 2012
Ah. yes. Path-MTU REQUIRES the DNF bit to be set... That's how it detects the requirement for the MTU to be adjusted (As you get back an ICMP error indicating the MTU that is necessary to cross a link when a packet can't be fragmented).

 

 

Sorry, thought you had an issue with the DNF being set somewhere.

 

 

H