How to force MTU on PPPoE interface

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hushcoden

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How to force MTU on PPPoE interface

« on: July 20, 2020, 09:27:53 pm »

I'd like to test MTU=1500 on my PPPoE interface, but if I enter the value on 'interfaces' -> 'wan' -> MTU and saving it doesn't actually change it (still 1492): is there a way perhaps through CLI to force the value to 1500?

Tia.

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Alphabet Soup

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Re: How to force MTU on PPPoE interface

« Reply #1 on: July 21, 2020, 01:54:15 pm »

Haven't done it myself but this thread from when RFC 4638 support was added to OPNsense should give you something to try: https://forum.opnsense.org/index.php?topic=2238.0

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franco

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Re: How to force MTU on PPPoE interface

« Reply #2 on: July 21, 2020, 04:01:03 pm »

If I recall correctly you actually have to input the oversize MTU of 1508 to reach the 1500 MTU?

Cheers,
Franco

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franco

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Re: How to force MTU on PPPoE interface

« Reply #3 on: July 21, 2020, 04:11:23 pm »

PS: Now I remember 8 byte is the PPPoE header that needs to be subtracted anyway

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hushcoden

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Re: How to force MTU on PPPoE interface

« Reply #4 on: July 21, 2020, 04:59:18 pm »

Thank you both, with 1508 it works

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