Ubuntu
isc-dhcp package

  1. Bug #930962
  2. Comment #0

Comment 0 for bug 930962

Revision history for this message
Tim Miller Dyck (timmillerdyck) wrote :

Tested with dhcp3-server ver. 3.1.3-2ubuntu3.3 in Ubuntu 10.04.3 Server, x64.

The DHCP server reports that UDP packets sent to it have bad checksums:

Feb 11 06:57:18 ... dhcpd: 5 bad udp checksums in 5 packets
Feb 11 06:58:22 ... dhcpd: last message repeated 7 times
Feb 11 06:59:17 ... dhcpd: last message repeated 7 times

The DHCP server host is a KVM virtual machine using a virtio-based virtual NIC.

This problem has been reported for other distros using KVM and virtio:

https://bugs.mageia.org/show_bug.cgi?id=1243

http://<email address hidden>/msg41958.html
 - suggests using iptables to write in a checksum

http://pkgs.fedoraproject.org/gitweb/?p=dhcp.git;a=blob;f=dhcp-4.2.2-xen-checksum.patch;h=038d346d726e131f1ab2579fe015a72b49733a0d;hb=HEAD
 - Fedora patch to dhcp to avoid this

The simplest workaround is to change the virtual NIC type from virtio to Intel e1000 in KVM. Apparently this driver calculates checksums. But virtio is the default driver type.

Thanks,
Tim Miller Dyck