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Webwally · Guest

Hi,

Does anyone know how to save an MTU setting in Mandrake 10.1? Reason being that my ISP is AOL and my MTU settings need to be 1400. They are 1500 by default, no probs in setting the MTU to 1400, upon rebooting the MTU goes back to 1500. Don't know how to save it.

[root@Mandrake jason]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:E0:4D:85:C4:FF
inet addr:10.0.0.3 Bcast:255.255.255.255 Mask:255.0.0.0
inet6 addr: fe80::2e0:4dff:fe85:c4ff/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1400 Metric:1
RX packets:5528 errors:0 dropped:0 overruns:0 frame:0
TX packets:6226 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2364445 (2.2 Mb) TX bytes:763605 (745.7 Kb)
Interrupt:5 Base address:0xc000
Cheers

Jason

mugstar · Posted: Thu Apr 21, 2005 6:34 pm Post subject: RE: Help!!!

AFAIK:
(as root)
Take the interface down: `ifdown eth0`
Set the MTU: `ifconfig eth0 mtu 1400`
Bring the interface back up`ifup eth0`

Hopefully if you reboot and do `ifconfig eth0` the setting should be as you want.

`man ifconfig` for more.

Guest · Posted: Thu Apr 21, 2005 7:06 pm Post subject: RE: Help!!!

Hi,

Tried the above, did'nt keep the setting.

Jason

mugstar · Posted: Thu Apr 21, 2005 8:02 pm Post subject: RE: Help!!!

Hokay.

Try editing /sys/class/net/eth0/mtu as root and make sure the correct value is there.

Rhakios · Posted: Thu Apr 21, 2005 8:11 pm Post subject: RE: Help!!!

From looking at the difference between Mandrake and SuSE, MTU can be set by editing /etc/sysconfig/network-scripts/ifcfg-eth0

At the moment it probably says something like

Guest · Posted: Thu Apr 21, 2005 9:43 pm Post subject: RE: Help!!!

Hi,
I entered /sys/class/net/eth0/mtu and got a message saying permission denied.

Andy · Posted: Thu Apr 21, 2005 9:51 pm Post subject:

Stupid question, I know, but did you try to access it as root?

AndyH

Guest · Posted: Thu Apr 21, 2005 9:54 pm Post subject:

Hi Andy,

Yes I did.

Jason

nelz · Posted: Thu Apr 21, 2005 9:54 pm Post subject:

/sys is a virtual filesystem, like /proc. any changes you make there won't survive a reboot. Rhakios' suggestion is the way to do it.
_________________
Unix is user-friendly. It's just very selective about who it's friends are.

Guest · Posted: Thu Apr 21, 2005 9:58 pm Post subject:

Hi,

Tried this, no sign of ifcfg-eth0 in this path /etc/sysconfig/network-scripts/ifcfg-eth0

Jason

mugstar · Posted: Thu Apr 21, 2005 10:00 pm Post subject:

The file ifcfg-eth0 is in the directory /etc/sysconfig/network-scripts/

Where does /sys/class/net/eth0/mtu take the value from if it's not included in /etc/sysconfig/network-scripts/ifcfg-eth0?

(Just curious...)

Rhakios · Posted: Thu Apr 21, 2005 11:56 pm Post subject:

Then do you have ifcfg-eth-anything-at-all? If you don't, I'm rather curious as to how your ethernet card works at all. SuSE usually names the ifcfg file after the mac address of the card, but my version of Mandrake (10.1 official) uses eth0. Have a look in /etc/sysconfig/network-scripts and see what else is there.
_________________
Bye, Rhakios

Guest · Posted: Fri Apr 22, 2005 9:53 am Post subject:

Hi,
found /etc/sysconfig/network-scripts/ifcfg-eth0, opened the file but could not edit it. Did'nt have permission!

Jason

Guest · Posted: Fri Apr 22, 2005 10:36 am Post subject:

Hi all,

Managed to edit the file and enter MTU=1400. Rebooted and guess what? Hooooray!!! It did as you said! rebooted at MTU 1400. All I can say is that you lads certainly know your stuff!!! and I'm greatfull for the help you all gave me!

P.S What a great website this is!!!

Cheers

Jason Wink

Guest · Posted: Fri Apr 29, 2005 8:17 pm Post subject:

**** you