Bug 8920

Summary: Can't set interface MTU with ifconfig
Product: [Retired] Red Hat Linux Reporter: eugene
Component: net-toolsAssignee: Crutcher Dunnavant <crutcher>
Status: CLOSED DUPLICATE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 6.1   
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2000-10-07 15:10:45 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 9215    
Bug Blocks:    

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
MTU.
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 ***