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Change MTU in interface PPPoE

luisfelipermluisfeliperm Newbie ✭
edited April 28 in Entry Level Firewalls

I activated Jumbo Frame on the Sonicwall NSV 270 and restarted the box. After that I changed the MTU of the parent interface (x2) to 1600. PPPoe runs on this x2 interface.
On the ISP side the PPPOE is at 1600, which allows me to use PPPOE MTU above 1492.
On the PPPOE Server, the MRU is at 1500, but Sonicwall does not negotiate above 1492. I would like to understand the reason for this limitation and if there is any way for me to increase the PPPoe protocol MTU to 1500, since the parent interface supports up to 1600.

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Category: Entry Level Firewalls
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  • CORRECT ANSWER
    luisfelipermluisfeliperm Newbie ✭
    Answer ✓

    As far as I remember, there is an RFC that recommends a size of 1480 or 1492 for the PPPOE MRU, but it is not a rule. After all, there are other devices that support mtu 1500, but apparently it doesn't work for Sonicwall.

Answers

  • ArkwrightArkwright Community Legend ✭✭✭✭✭

    There's an RFC for this [can't remember the number off the top of my head] but SonicOS does not support it, so you're stuck with 1492.

  • ArkwrightArkwright Community Legend ✭✭✭✭✭

    RFC 4638.

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