Baby jumbo frames (MTU 1508) on PPPoE connections



  • Does anybody know if one can configure an MTU of 1508 on PPPoE wan connections?  Either by setting it manually, or negotiated via http://tools.ietf.org/html/rfc4638

    FWIW, this question has been asked before:

    https://forum.pfsense.org/index.php?topic=61876.0

    But the question was left open.

    This is a pretty big deal on UK FTTP connections.  At the moment the only confirmed solutions are the BT HH (which is a terrible device), routeros (requires manual MTU configuration), and Firebrick (which are very expensive for home setups).  It would be great to have pfsense provide a fully functional solution.



  • The question is: Is there an option under WAN - PPPoE?

    Answer: Yes, see pic

    Or did you ask for something different?

    ![pppoe mtu.jpg](/public/imported_attachments/1/pppoe mtu.jpg)
    ![pppoe mtu.jpg_thumb](/public/imported_attachments/1/pppoe mtu.jpg_thumb)



  • You can set it but it appears to get ignored and the pppoe1 interface always gets set as 1492.

    Last I heard jumbo frame support didn't get added to the FreeBSD version of PPPd (2.4.6) until January this year.  But I'm unaware if the latest update (pfsense 2.1.1) includes this newer version.

    I know if I manually ifconfig pppoe1 mtu1508 packets still get fragmented,  which is a shame.


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