Pppoe mtu fixed at 1492, bug with interfaces_ppps_edit.php

  • I'm running current snapshot (Fri Oct 5 19:42:06 EDT 2012),  and was trying to set my pppoe mtu to 1500 (as opposed to 1492), since my
    ISP allows for bigger frames. However, no matter what I put as MTU size in the PPPoE interface, the generated pppoe0 interface still
    shows up with mtu 1492 (i even patched interfaces.php to also set mru and mrru to the same value as mtu):

    grep mtu /var/etc/mpd_opt4.conf

    set link mtu 1508

    pppoe0: flags=88d1 <up,pointopoint,running,noarp,simplex,multicast>metric 0 mtu 1492
            inet6 fe80::250:c2ff:fe21:23f4%pppoe0 prefixlen 64 scopeid 0x18
            inet x.x.x.x –> x.x.x.x netmask 0xffffffff
            nd6 options=3 <performnud,accept_rtadv>I made sure the parent interfaces have a highter mtu:

    em3: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1600

    em3_vlan11: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1508

    (pppoe runs on vlan11 em3)

    Is there some way I can get mpd to actually honor the configured mtu?

    I tried to check what advanced options I could tweak, but the whole GUI froze when clicking interfaces_ppps_edit.php. Turns out this
    interprets my serial console somehow as a possible modem connection and sends "AT OK" commands out the tty (thereby also
    disabling the console completely).  Killing the lighttpd and after a while restarting it fixes the freeze, but doesn't reenable the console.
    "Fixing" interfaces_ppps_edit.php the following way:

    if (!is_dir("/var/spool/lock"))
                                            mwexec("/bin/mkdir -p /var/spool/lock");
                                    $serialports = array(); #pfSense_get_modem_devices();
                                    $serport_count = 0;

    (don't call pfSense_get_modem_devices()) fixes the problem for me, but is obviously not the right fix for everyone.


  • pppoe mtu fixed at 1492 is a known bug(enhancement) for 6 months plus, pppoe will ways connect at 1492 even if you manually try to insinuate from command line. also it suppose to auto negotiate the mtu but never worked for me. Not everyone has this problem so it doesn't get fixed, personal i didn't have this problem till my isp updated there servers in june and now no internet through pfsense. lucky for me i just swapped it out but i do want pfsense back so i keep checking the forum each month seeing more and post about or related to the issue.

    interfaces_ppps_edit.php you can change the code and put the settings back on the page but it will make no difference. been there done that

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