On 03/11/2010 02:14 PM, Joe Conway wrote: > In the last few days I've noticed network connectivity issues from > multiple virtual machines (fedora, centos, winxp) running on a fedora 12 > host. What seemed odd was that I could ping by host name, showing that > both the basic network functionality as well as DNS was working. What > was failing was browser access to any site outside my own subnet. > > I'm reasonably sure the issue is the MTU setting for my host bridge > (br0) interface. It currently shows: > > # ifconfig > br0 [...] > UP BROADCAST RUNNING PROMISC MULTICAST MTU:576 Metric:1 > [...] > > I would have expected MTU:1500. In fact most of the examples I've found > show other people with br0 having MTU=1500. > > My short term workaround has been to manually set MTU to 576 in each of > my VMs. This works, but I'm wondering: > > 1) Have others seen this? > 2) Is there any way to manually increase MTU for the bridge interface? > > WRT #2, I tried: > > ifconfig br0 mtu 1500 > > and get this error: > > SIOCSIFMTU: Invalid argument > > I also tried adding MTU=1500 to ifcfg-br0. No joy. > > Any ideas? "brctl show" will show how all the bridges are built. Check all interfaces under "ifconfig -a" and see if any of the participants in the bridge have a small MTU. IIRC, the smallest MTU will be propagated to the bridge so it doesn't overrun the least-capable interface. ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer, C2 Hosting ricks@xxxxxxxx - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - When you don't know what to do, walk fast and look worried. - ---------------------------------------------------------------------- -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
