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Bug 8920 - Can't set interface MTU with ifconfig
Summary: Can't set interface MTU with ifconfig
Status: CLOSED DUPLICATE of bug 9215
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: net-tools
Version: 6.1
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Crutcher Dunnavant
QA Contact:
Depends On: 9215
TreeView+ depends on / blocked
Reported: 2000-01-27 14:35 UTC by eugene
Modified: 2008-05-01 15:37 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2000-10-07 15:10:45 UTC

Attachments (Terms of Use)

Description eugene 2000-01-27 14:35:39 UTC
Trying to set the MTU value for an interface:
ifconfig eth0 mtu 1400
--causes the following error.
SIOCSIFMTU:Invalid argument

A workaround appears to be:
echo 1 > /proc/sys/net/ipv4/ip_always_defrag
echo 1 > /proc/sys/net/ipv4/ip_no_pmtu_disc

This error occurred after upgrading to 6.1.
I was able to use ifconfig to set the MTU on a different machine (identical
processors and ethernet cards) that had 6.1 installed on it originally.

Comment 1 Elliot Lee 2000-02-03 20:29:59 UTC
I can't reproduce this problem on either of my boxen. It may be that your
networking configuration is different on the upgraded system, and a
feature/limitation of the kernel or hardware is preventing you from changing the

Comment 2 Jeff Johnson 2000-10-07 15:08:53 UTC

*** This bug has been marked as a duplicate of 9129 ***

Comment 3 Jeff Johnson 2000-10-07 15:11:14 UTC

*** This bug has been marked as a duplicate of 9215 ***

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