Latest nvnet network driver prevents setting MTU < 1500

[drrandom]

I have an nforce2 based motherboard, and recently upgraded from Mandrake 9.2 to 10.0 (a bit late you might say). I am using the 2.6.3-7 kernel build.

I have the latest (6111 think?) nforce drivers installed, and everything seems to be working well, except that the nvnet driver refuses to let me set the MTU to a value less than 1500. This is the maximum size of network packets, and given that somewhere on my ADSL connection the fragment messages are lost, I have to set this to 1458 or less for certain things to work (sending large emails, visiting some websites).

I think this might also explain some of the earlier posts, specifically to do with visiting websites with content bigger than a certain size.

Looking at the nvidia documentation, it suggests MTU should be set to a value between 1500 and 9000ish, but I always used to have it set to 1458 with a previous nvnet driver.

Anyone got any ideas as to how I can change this?

The symptoms are:

"ifconfig eth0 mtu 1458"
results in the error message

"SIOCSIFMTU: Invalid argument"


Thanks for any help,

Cheers,

Tim

[drrandom]

replying to my own post.....

I changed to the forcedeth driver (alias eth0 forcedeth) instead of the nvnet driver, and everything works fine, I can set the MTU value to whatever is required. Anyone else seeing odd network problems with sites above a certain size, or emails bigger than a certain size failing should probably try this....

(FI, by editing /etc/sysconfig/network-scripts/ifcfg-eth0 and adding MTU=xxxx - in my case xxxx=1458)

Seems an odd restriction to make in a network driver, I thought any packet size was valid, right down to 0 (not that just sending the header and no data would do you any good, but hey).

Cheers,

Tim

[ahpook]

You are right that any value should be OK, and I agree that this is a weird lapse on the
part of the nvidia driver, but I would point out (having had similar trouble myself) that this
is at least documented in the release notes, under "Module Parameters"

MTU
The "mtu" module parameter controls the MTU size in bytes. This parameter takes a value between 1500 and 9202, inclusive. By default, a 1500 byte MTU is used. This parameter is only relevant when hardware offload mode is turned on.