Ubuntu
network-manager package

Bad MTU for eth0 in 9.04 amd64

Bug #352779 reported by Paolo Montrasio
4
Affects Status Importance Assigned to Milestone
network-manager (Ubuntu)
Fix Released
High
Alexander Sack
Ubuntu ubuntu-9.04
Jaunty
Fix Released
High
Alexander Sack
Ubuntu ubuntu-9.04

Bug Description

I tried the latest 9.04 live cd on a hp nc8430 and I couldn't get a working wired network connection.
"ifconfig -a" reported a MTU set to 64 bytes. I changed it to 1500 with "sudo ifconfig eth0 mtu 1500"
"ifconfig -a" confirmed the change but the connection didn't work.
I set the MTU to 1500 in the Network Connection panel, Auto eth0, Edit and it started working.

The point is why did it set the MTU so low? The same pc/ISP/router got the correct MTU with ubuntu 8.10 and WinXP.

Revision history for this message
Kees Cook (kees) wrote :

Can you please report the output of the following command: ls -la /sbin/dhclient-script /etc/dhcp3/dhclient-script

affects: ubuntu → dhcp3 (Ubuntu)
Changed in dhcp3 (Ubuntu):
importance: Undecided → High
status: New → Incomplete
Revision history for this message
Kees Cook (kees) wrote :

For some background, the script /sbin/dhclient-script should have an MTU filter that would keep such values from getting set.

Kees Cook (kees)
tags: added: regression-potential
Steve Beattie (sbeattie)
Changed in dhcp3 (Ubuntu Jaunty):
assignee: nobody → kees
Revision history for this message
Steve Langasek (vorlon) wrote :

Note that if you are using NetworkManager for your connection, it bypasses the dhcp3-client dhclient-script in favor of its own binary(!).

Revision history for this message
Paolo Montrasio (paolo-paolomontrasio) wrote :

> Can you please report the output of the following command: ls -la /sbin/dhclient-script /etc/dhcp3/dhclient-script

$ ls -l /sbin/dhclient*
lrwxrwxrwx 1 root root 9 2009-03-23 23:56 /sbin/dhclient -> dhclient3
-rwxr-xr-x 1 root root 448584 2009-03-17 23:05 /sbin/dhclient3
-rwxr-xr-x 1 root root 8714 2009-03-17 23:05 /sbin/dhclient-script

I don't have /etc/dhcp3/dhclient-script on my live cd. These are the contents of /etc/dhcp3

$ find /etc/dhcp3/ -ls
  1421 0 drwxr-xr-x 4 root root 92 Mar 23 23:57 /etc/dhcp3/
 22035 0 drwxr-xr-x 2 root root 50 Mar 24 00:17 /etc/dhcp3/dhclient-enter-hooks.d
 22038 2 -rwxr-xr-x 1 root root 1037 Mar 23 10:19 /etc/dhcp3/dhclient-enter-hooks.d/avahi-autoipd
 22039 2 -rw-r--r-- 1 root root 1058 Mar 17 23:05 /etc/dhcp3/dhclient-enter-hooks.d/debug
 22040 2 -rwxr-xr-x 1 root root 1736 Mar 16 16:01 /etc/dhcp3/dhclient-enter-hooks.d/samba
 22036 0 drwxr-xr-x 2 root root 85 Mar 24 00:16 /etc/dhcp3/dhclient-exit-hooks.d
 22041 2 -rw-r--r-- 1 root root 1060 Mar 17 23:05 /etc/dhcp3/dhclient-exit-hooks.d/debug
 22042 1 -rw-r--r-- 1 root root 802 Mar 21 00:51 /etc/dhcp3/dhclient-exit-hooks.d/ntpdate
 22043 2 -rw-r--r-- 1 root root 1498 Mar 17 23:05 /etc/dhcp3/dhclient-exit-hooks.d/rfc3442-classless-routes
 22044 2 -rwxr-xr-x 1 root root 1039 Mar 23 10:19 /etc/dhcp3/dhclient-exit-hooks.d/zzz_avahi-autoipd
 22037 2 -rw-r--r-- 1 root root 1703 Mar 17 23:04 /etc/dhcp3/dhclient.conf

Revision history for this message
Kees Cook (kees) wrote :

Alexander, what do you think of this patch? It mimics the behavior we have in dhcp3 (see bug 274069).

Changed in dhcp3 (Ubuntu Jaunty):
assignee: kees → asac
status: Incomplete → In Progress
Revision history for this message
Alexander Sack (asac) wrote :

committed to nm upstream.

affects: dhcp3 (Ubuntu Jaunty) → network-manager (Ubuntu Jaunty)
Changed in network-manager (Ubuntu Jaunty):
status: In Progress → Fix Committed
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package network-manager - 0.7.1~rc4.1.cf199a964-0ubuntu1

---------------
network-manager (0.7.1~rc4.1.cf199a964-0ubuntu1) jaunty; urgency=low

  * upstream release 0.7.1 final candidate 1 (Wed Apr 8 06:38:37 2009 -0400)
    + http://git.freedesktop.org/NetworkManager/NetworkManager/
    + NETWORKMANAGER_0_7 (branch)
      - modem-probe: retry opening the serial port if --delay is used (LP: #351803)
        (Up to --delay milliseconds.)
      - core: ignore DHCP-sent MTUs less than 577 (LP: #352779)
      - core: update FSF address (bgo #577949)
      - modem-probe: don't restrict probing on tty device name (LP: #351803)

 -- Alexander Sack <email address hidden> Wed, 08 Apr 2009 12:53:41 +0200

Changed in network-manager (Ubuntu Jaunty):
status: Fix Committed → Fix Released
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