Reduce Ethernet MTU

Hello,
I want to know if i set some linux machines with MTU 1492 and some
1500 in a LAN of 10 computers does they work?
I am using Redhat 9 with kernel 2.4.24. I will be setting MTU 1492 in
kernel source code.
regards,
cranium.

kernel.lover wrote:

> Hello,
> I want to know if i set some linux machines with MTU 1492 and some
> 1500 in a LAN of 10 computers does they work?
> I am using Redhat 9 with kernel 2.4.24. I will be setting MTU 1492 in
> kernel source code.

They should be OK. Most computers these days, use MTU discovery, which
tells the originating computer the largest MTU, that will make it to the
other end. Failing that, packets can be fragmented, if allowed.

On 6 Feb 2005 11:04:02 -0800, kernel.lover <(E-Mail Removed)> wrote:
> Hello,
> I want to know if i set some linux machines with MTU 1492 and some
> 1500 in a LAN of 10 computers does they work?
> I am using Redhat 9 with kernel 2.4.24. I will be setting MTU 1492 in
> kernel source code.

Why in kernel source code (you can change mtu on the fly with ifconfig)?

The first I had to mess with mtu was attempting to receive smtp mail
behind a hardware PPPoE router. Mail larger than packet size would not
arrive (timeout waiting for data transfer) until I set LAN nic of server
to mtu 1492.

But one thing I noticed even with LAN nic at mtu 1492 (which shows in
ifconfig), is that it still uses mtu 1500 within my LAN (confirmed by ping
-s 1472 -M do). But through the PPPoE connection that fails if -s is
greater than 1464 (ping data + 28 = mtu).