Oversized Frames



  • Hi, I'm getting an oversize frame error and I was wondering if it's being caused by my card not fully supporting VLANs.
    The lengths is dropping are standard 1514 frames because it says the max is 1510.
    Would changing to a different NIC potentially fix the problem?

    Jul 11 11:38:27 kernel: vr1: discard oversize frame (ether type 800 flags 3 len 1518 > max 1514)
    Jul 11 11:38:27 kernel: vlan8: discard oversize frame (ether type 800 flags 3 len 1514 > max 1510)
    Jul 11 11:38:30 kernel: vlan6: discard oversize frame (ether type 800 flags 403 len 1514 > max 1510)
    Jul 11 11:38:33 kernel: vlan8: discard oversize frame (ether type 800 flags 3 len 1514 > max 1510)
    Jul 11 11:38:39 kernel: vlan6: discard oversize frame (ether type 800 flags 3 len 1514 > max 1510)
    Jul 11 11:38:39 kernel: vlan7: discard oversize frame (ether type 800 flags 403 len 1514 > max 1510)

    I have checked the other results in the forum, but this is happening to the VLAN interfaces and the LAN



  • Hi,

    I got the exact same problem and it is very annoying. It's been two days I'm looking for solutions all over the web for solutions. I got some clues about what is wrong but no solution…

    Here's my config :

    I have 1 alix 2C3 Box running pfsense 1.2 Release. It's connected to a Linksys SRW224G4 with a 802.1Q trunk. I think the problem comes from this trunk.

    it seems that an easy and quick solution would be to be able to raise the acceptable frame size to 1514. I don't know how to do that.
    Not really "elegant" but would do for now.

    The question is more about to know if the switch sends frames too big or if the alix box doesn't accept 802.1Q properly.

    Can anyone help me ?

    Thanks :)



  • It seemed that my card wasn't accepting the 802.1Q tagged frames correctly if the original frame at the maximum size. Switching to a different network card fixed the problem for me.



  • Hello!

    Someboby posted the same problem at the Spanish section:

    I think the NIC doesn't have full support for VLAN. Please see at:

    http://www.freebsd.org/cgi/man.cgi?query=vlan&apropos=0&sektion=0&manpath=FreeBSD+6.2-RELEASE&format=html

    and specially where it says:

    The interfaces that support oversized frames are as follows:

    Regards,

    Josep Pujadas



  • Ouch. That sounds like Alix 2C3 boards actually don't really support vlans…

    But that sounds really really strange regarding this page :
    http://cvstrac.pfsense.com/chngview?cn=20586

    So, either I have 2 messed up boxes, or pcengines changed some hardware stuff recently, or I missed something somewhere...

    Thanks for your answer. Any more hint would be welcome.



  • But that sounds really really strange regarding this page :
    http://cvstrac.pfsense.com/chngview?cn=20586

    It seems like pfSense developpers modified FreeBSD 6.2 kernel to support VLAN with vr(4) driver.

    FreeBSD 7.0 has vr(4) included for "long frames for vlan natively":

    http://www.freebsd.org/cgi/man.cgi?query=vlan&apropos=0&sektion=0&manpath=FreeBSD+7.0-stable&format=html

    Perhaps the modifications done to the pfSense 1.2 kernel were FreeBSD 7.0 based. pfSense 1.2 is FreeBSD 6.2 based.

    Regards,

    Josep Pujadas



  • Well, thanks for your answer but, I'm not sure how to understand it… what would that mean ? That pfsense 1.2 does or does not support 802.1Q on vr(4) driver ?

    I'm still trying to find out if the firewall or the switch is at fault  ??? :-\

    I can't find anything special on the switch (there's not that many options and I sure wish it was a cisco...)

    thanks again.



  • There's not much you can do on a switch. If a client sends that maximum frame size, the switch just adds it's VLAN tags like it is supposed to. The only potential fix on a switch would be to fragment the packets, but the switch shouldn't do that at all if it's strictly layer 2. If the switch was dropping oversized packets, you wouldn't see anything about it in the pfSense logs. It's an issue with the card.



  • That pfsense 1.2 does or does not support 802.1Q on vr(4) driver ?

    I think it should, because developers modified the kernel for pfSense 1.2.

    http://cvstrac.pfsense.com/chngview?cn=20586 (as you posted)

    However, I surfed the kernel source for vr(4) and I couldn't find any differences (http://fxr.watson.org) between 6.2 & 7.0 releases.

    Perhaps the 6.2 documentation about vlan(4) is not correct.

    May be pfSense developers can answer your question or you could post your problem in a FreeBSD mailing list:

    http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/eresources.html#ERESOURCES-MAIL

    (CURRENT is a good list for questions like this).

    Regards,

    Josep Pujadas



  • That's a glitch in FreeBSD prior to 6.3, where MRU == MTU, so it won't receive anything larger than MTU. That's wrong and can break things like VLANs. You won't see this in 1.2.1, nor the 6.3-based 1.2 here. http://cvs.pfsense.org/~sullrich/testing_images/6/FreeBSD_RELENG_6_3/pfSense_RELENG_1_2/



  • Sorry for not responding sooner (I guess you guys know what it is to be overwhelmed by work… :-)

    bellera, thanks a lot for your help, you saved me a lot of time. cmb, thanks for your solution, I'll try switching to 1.2.1 asap and check if it fixes my problem. I'll let you know :)

    Again, thanks a lot.



  • Just to let you guys know : I've installed PFSense 1.2.1 about a month ago and it indeed fixed the problem. I've met a few crashes during the configuration of the boxes but it's been rock stable since.

    So, again, thanks for your help.


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