PPPOE, MTU, and boom.

Alex Rubenstein alex at nac.net
Wed Jul 18 07:35:33 UTC 2001

On Wed, 18 Jul 2001, Alex Rubenstein wrote:

> It allows you to tinker with the Windows settings of TCP. I adjusted MTU
> to 1400, wham-o, all the sites I listed started working; including, what I
> didn't list before, the downloading of transactions via Quicken. Seems to
> be a fixall.

I can tell it's getting late, when I reply to myself.

In the scenerio where you have a router be the PPPOE client (in my test
case, it's a Cisco 827 running 12.1(3)XG4), things are still somewhat
broken. The 827 is routing between an ethernet and a PPPOE session, and
even with the 827 having the MTUs at 1492 or 1400, windoze boxen are still
stuck up there at 1500 and those sites don't work. I then use Mr. TCP and
set the ethernet card of the windows box to a MTU of 1400, and voila, it

This really sucks for those folks who will have many machines bechind said
router; it will require a Mr. TCP on each and every one of them.


-- Alex Rubenstein, AR97, K2AHR, alex at nac.net, latency, Al Reuben --
--    Net Access Corporation, 800-NET-ME-36, http://www.nac.net   --

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