MTU - Revision history

Mcefan at 11:48, 8 October 2012

2012-10-08T11:48:01Z

←Older revision		Revision as of 11:48, 8 October 2012
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	{{versioninfo}}		{{versioninfo}}
	[[Category: Networking]]		[[Category:Networking\|*Network Setup,MTU]]
	[[Category: Troubleshooting]]		[[Category:Troubleshooting]]

	Ever had problems with your MTU being set to 576 on eth0 because of your ISP or other reasons. You can fix that.		Ever had problems with your MTU being set to 576 on eth0 because of your ISP or other reasons. You can fix that.

Marie.o: Mtu moved to MTU

2011-11-06T11:57:25Z

Mtu moved to MTU

←Older revision	Revision as of 11:57, 6 November 2011
(No difference)

Wierdbeard65 at 08:45, 5 May 2010

2010-05-05T08:45:21Z

←Older revision		Revision as of 08:45, 5 May 2010
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			{{versioninfo}}
	[[Category: Networking]]		[[Category: Networking]]
	[[Category: Troubleshooting]]		[[Category: Troubleshooting]]

Chris Caven at 19:27, 20 April 2010

2010-04-20T19:27:01Z

←Older revision		Revision as of 19:27, 20 April 2010
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	[[Category: Troubleshooting]]		[[Category: Troubleshooting]]

	Ever had problems with your MTU being set to 576 on eth0 because of ~~you~~ ISP or other reasons. You can fix that.		Ever had problems with your MTU being set to 576 on eth0 because of your ISP or other reasons. You can fix that.

	~~you~~ can check your ~~mtu~~ settings with the terminal command:		You can check your MTU settings with the terminal command:
	ifconfig eth#		ifconfig eth#
	where eth# is the ~~nic~~ you are trying to affect in my case this was eth0		where eth# is the NIC you are trying to affect; in my case this was eth0


	Realtime you can open a terminal and use:		Realtime you can open a terminal and use:
	sudo ifconfig eth0 mtu ####		sudo ifconfig eth0 mtu ####
	The #### is the number of the ~~mtu~~ you want to use in my case 1500, so the realtime command would be: sudo ifconfig eth0 mtu 1500		The #### is the number of the MTU you want to use; in my case 1500, so the realtime command would be: sudo ifconfig eth0 mtu 1500

			Of course, if you reboot or the network gets restarted it will change to 576 again, so to make it permanent we have to edit some files, in particular the /etc/network/interfaces file.

	~~Ofcourse if you reboot or the network gets restarted it will change to 576 again, so to make it permanent we have to edit some files, in particular the /etc/network/interfaces file.~~		/etc/network/interfaces looks like this for a normal core on LinuxMCE:

	/etc/network/interfaces looks like this for a normal core on ~~linuxmce~~:

	auto lo		auto lo
Line 27:		Line 25:
	netmask 255.255.255.0		netmask 255.255.255.0

	So eth0 is getting ~~it's ip~~ from your ~~isp~~ through ~~dhcp~~ and ~~therefor~~ also the ~~mtu~~ setting		So eth0 is getting its IP from your ISP through DHCP and therefore also the MTU setting; eth1 is getting a static IP that's provided.
	~~Eth1~~ is getting a static ip that's provided.

			Now the changes you want to make to ensure the MTU is 1500 for everything are the following....

	~~Now~~ the ~~changes~~ you ~~want~~ to ~~make~~ to ~~make sure~~ the ~~mtu is~~ 1500 ~~for everything are the following....~~		For the DHCP eth0, you need to add a line telling the NIC to set the MTU at 1500 which looks like this:-


	~~For the dhcp eth0 you need to add a line telling the nic to set the mtu at 1500 which looks like this~~
	post-up /sbin/ifconfig $IFACE mtu 1500		post-up /sbin/ifconfig $IFACE mtu 1500

			For the static eth1, it's easier to add a line telling the MTU to be 1500 (or whatever you like, you can experiment with your internal network for better package handling. I've heard up to 9000, but this is up to you)

	For the static eth1 it's easier and you can add a line telling the mtu to be 1500 (or whatever you like, you can experiment with your internal network for better package handling, i've heard up to 9000, but this is up to you)
	mtu 1500		mtu 1500

			Your interfaces file should now look something like this:-
	Your interfaces file should now look something like this:

	auto lo		auto lo
Line 55:		Line 50:
	mtu 1500		mtu 1500

	~~after~~ a networking restart:		After a networking restart:
	/etc/init.d/networking restart		/etc/init.d/networking restart

	look at your ifconfig again and it should have the correct ~~mtu~~ settings		look at your ifconfig again and it should have the correct MTU settings.


	Hope this helps~~, please~~ add ~~aditional~~ information if needed/wanted.		Hope this helps. Please add additional information if needed/wanted.

Rperre at 14:30, 20 October 2009

2009-10-20T14:30:47Z

←Older revision		Revision as of 14:30, 20 October 2009
Line 1:		Line 1:
	[[Category: ~~LinuxAdmin~~]]		[[Category: Networking]]
			[[Category: Troubleshooting]]

	Ever had problems with your MTU being set to 576 on eth0 because of you ISP or other reasons. You can fix that.		Ever had problems with your MTU being set to 576 on eth0 because of you ISP or other reasons. You can fix that.

	you can check your mtu settings with the terminal command: ifconfig eth#		you can check your mtu settings with the terminal command:
			ifconfig eth#
	where eth# is the nic you are trying to affect in my case this was eth0		where eth# is the nic you are trying to affect in my case this was eth0

	Realtime you can open a terminal and use: sudo ifconfig eth0 mtu ####
			Realtime you can open a terminal and use:
			sudo ifconfig eth0 mtu ####
	The #### is the number of the mtu you want to use in my case 1500, so the realtime command would be: sudo ifconfig eth0 mtu 1500		The #### is the number of the mtu you want to use in my case 1500, so the realtime command would be: sudo ifconfig eth0 mtu 1500


	Ofcourse if you reboot or the network gets restarted it will change to 576 again, so to make it permanent we have to edit some files, in particular the /etc/network/interfaces file.		Ofcourse if you reboot or the network gets restarted it will change to 576 again, so to make it permanent we have to edit some files, in particular the /etc/network/interfaces file.

	~~This~~ looks like this for a normal core on linuxmce:		/etc/network/interfaces looks like this for a normal core on linuxmce:

	auto lo		auto lo
Line 23:		Line 29:
	So eth0 is getting it's ip from your isp through dhcp and therefor also the mtu setting		So eth0 is getting it's ip from your isp through dhcp and therefor also the mtu setting
	Eth1 is getting a static ip that's provided.		Eth1 is getting a static ip that's provided.


	Now the changes you want to make to make sure the mtu is 1500 for everything are the following....		Now the changes you want to make to make sure the mtu is 1500 for everything are the following....


	For the dhcp eth0 you need to add a line telling the nic to set the mtu at 1500 which looks like this		For the dhcp eth0 you need to add a line telling the nic to set the mtu at 1500 which looks like this
	post-up /sbin/ifconfig $IFACE mtu 1500		post-up /sbin/ifconfig $IFACE mtu 1500


	For the static eth1 it's easier and you can add a line telling the mtu to be 1500 (or whatever you like, you can experiment with your internal network for better package handling, i've heard up to 9000, but this is up to you)		For the static eth1 it's easier and you can add a line telling the mtu to be 1500 (or whatever you like, you can experiment with your internal network for better package handling, i've heard up to 9000, but this is up to you)
	mtu 1500		mtu 1500

	Your interfaces file should look something like this ~~now~~:
			Your interfaces file should now look something like this:

	auto lo		auto lo
Line 47:		Line 57:
	after a networking restart:		after a networking restart:
	/etc/init.d/networking restart		/etc/init.d/networking restart

	look at your ifconfig again and it should have the correct mtu settings		look at your ifconfig again and it should have the correct mtu settings


	Hope this helps, please add aditional information if needed/wanted.		Hope this helps, please add aditional information if needed/wanted.

Ray N: Added page category

2009-10-19T21:00:08Z

Added page category

←Older revision		Revision as of 21:00, 19 October 2009
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			[[Category: LinuxAdmin]]
	Ever had problems with your MTU being set to 576 on eth0 because of you ISP or other reasons. You can fix that.		Ever had problems with your MTU being set to 576 on eth0 because of you ISP or other reasons. You can fix that.

Rperre: changing mtu size in linuxmce ubuntu

2009-10-19T15:42:32Z

changing mtu size in linuxmce ubuntu

New page

Ever had problems with your MTU being set to 576 on eth0 because of you ISP or other reasons. You can fix that.

you can check your mtu settings with the terminal command: ifconfig eth#
where eth# is the nic you are trying to affect in my case this was eth0

Realtime you can open a terminal and use: sudo ifconfig eth0 mtu ####
The #### is the number of the mtu you want to use in my case 1500, so the realtime command would be: sudo ifconfig eth0 mtu 1500

Ofcourse if you reboot or the network gets restarted it will change to 576 again, so to make it permanent we have to edit some files, in particular the /etc/network/interfaces file.

This looks like this for a normal core on linuxmce:

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
auto eth1
iface eth1 inet static
address 192.168.80.1
netmask 255.255.255.0

So eth0 is getting it's ip from your isp through dhcp and therefor also the mtu setting
Eth1 is getting a static ip that's provided.

Now the changes you want to make to make sure the mtu is 1500 for everything are the following....

For the dhcp eth0 you need to add a line telling the nic to set the mtu at 1500 which looks like this
post-up /sbin/ifconfig $IFACE mtu 1500

For the static eth1 it's easier and you can add a line telling the mtu to be 1500 (or whatever you like, you can experiment with your internal network for better package handling, i've heard up to 9000, but this is up to you)
mtu 1500

Your interfaces file should look something like this now:

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
post-up /sbin/ifconfig $IFACE mtu 1500
auto eth1
iface eth1 inet static
address 192.168.80.1
netmask 255.255.255.0
mtu 1500

after a networking restart:
/etc/init.d/networking restart
look at your ifconfig again and it should have the correct mtu settings

Hope this helps, please add aditional information if needed/wanted.