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Wrong MTU for pppoe

asked 2016-09-20 07:37:35 -0500

Sergey2016 gravatar image


I don't know whether this is a bug or not, I'm not a network specialist, but since some update, Network Manager sets incorrect MTU value for my DSL connection. MTU change in the Network Manager from auto to 1492 under Ethernet tab for both enp4s0 and the connection doesn't help. Adding MTU=1492 to etc/sysconfig/network-scripts/ifcfg-enp4so doesn't help either. The solution for me is to run "ip link set mtu 1492 dev enp4s0" in the terminal on every boot. So the question is: Is there another solution that would set MTU permanenetly?


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answered 2016-09-21 15:35:46 -0500

sixpack13 gravatar image

updated 2016-09-22 08:26:30 -0500

FranciscoD_ gravatar image

you are correct, sysctl --system with an extra file under /etc/sysctl.d/ doesn't change anything.

SORRY !!! My bad. BUG / Feature / PEBKAC ???

please delete your /etc/sysctl.d/100-my-MTU.conf !

what's about an rc.local ? place a file called rc.local with the following text under /etc/rc.d/

touch /var/lock/subsys/local
ifconfig enp4s0 mtu 1492;
exit 0;

rights and ownership should be this:

-rwx------. 1 root root 4,6K  4. Jun 19:56 rc.local

reboot or su -c 'source /etc/rc.d/rc.local'

check your MTU with ifconfig | grep mtu OR tracepath

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Thanks, this works perfectly! MTU is set to 1492!

Sergey2016 gravatar imageSergey2016 ( 2016-09-21 21:17:35 -0500 )edit

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Asked: 2016-09-20 04:05:25 -0500

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Last updated: Sep 22 '16