On Mon, Nov 15, 2004 at 01:32:43PM -0500, Iain McBride wrote: > While everything I can find online regarding the e100 driver in 2.6 > kernels not needing a patch to avoid MTU issues with VLAN tagging, I've > been unsuccessful in getting VLAN-tagged connections to function properly. > > VLAN router: 2x e100 NICs, 2.6.8.1 Linux kernel, VLANs config'd > > Switch: Cisco 2924, trunk enabled on the VLAN router's port, end > machine's port assigned to proper VLAN > > End machine: e100 NIC, 2.6.8.1 Linux kernel, normal interface config > > When I take another machine and put its switch port into a VLAN, I > experience the strange behaviour typical of MTU issues unless I configure > the end machine with an MTU of around 1468 or smaller. Large file This is plain weird. If you had 802.1Q problems the MTU problem should dissappears with MTU=1496 (the tag is only 4 bytes). Any lower indicates problems that are not 4 byte tag related. > transfers time out, packets silently dropped can't ping with 1500 byte > packet payload, etc. > > If I remove the VLAN trunking and bring up the router interface in the > normal fashion, everything is fine. > > Any hints on further troubleshooting? Jup: tcpdump the interface (-s 1500) and start pinging with a size that makes it almost fragment (so with 6 different sizes actually). The tcpdump should be done on the machine with the 802.1Q tag, and one without the 802.1Q tag. And please make sure you are using the e100 driver and not the eepro100. -- begin LOVE-LETTER-FOR-YOU.txt.vbs I am a signature virus. Distribute me until the bitter end
