Solved: Re: AnyConnect NAM MTU

avallely · ‎08-17-2021

Customer has deployed AnyConnect NAM, but is not using MACsec. It is clearly documented using the NAM will reduce the MTU from 1500 to 1468. Can the customer change the MTU back to 1500 without any problems, or is there a requirement to remain at 1468

stsargen · ‎08-17-2021

NAM has no requirement to have the MTU set at 1468 unless using MacSec. The MTU is set at driver install time in case a MacSec configuration is loaded. The only problem I can see with changing the MTU back to 1500 is that it could change back if NAM triggers any type of driver reinstall. This can happen under certain circumstances when we detect issues with our filter driver.

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stsargen · ‎08-17-2021

NAM has no requirement to have the MTU set at 1468 unless using MacSec. The MTU is set at driver install time in case a MacSec configuration is loaded. The only problem I can see with changing the MTU back to 1500 is that it could change back if NAM triggers any type of driver reinstall. This can happen under certain circumstances when we detect issues with our filter driver.

avallely · ‎08-19-2021

Thank you.