Netgear WGT624v2 MTU Problem With PPPoE

[patinsj]

OK I know this is kind of long and complicated but please read the whole thing.

First my setup

Netgear WGT624v2 wireless router
Hardware Version V3 (according to router config page)
Firmware Version V4.2.6_1.0.1

Connected to Covad 1.5Mb DSL though Broadxent 8012-V DSL modem
One computer connected directly to router running Win XP SP2,
two others though wireless, one running Win XP SP2, and the other running Win 98SE,
all 3 computers exhibit this problem.


The problem is that according to these two web sites

speedguide.net - TCP-IP Analyzer
http://www.speedguide.net/analyzer.php

broadbandreports.com - Tweak Test
http://www.broadbandreports.com/tweaks

My MTU is 40 bytes lower than what is set in the router config.
For example, I set the MTU to 1492 for my PPPoE connection and these two sites say its set at 1452

The weird thing is if I use the ping command and ping a website with the -F (don’t fragment packet) and -L 1464 (sends a 1464 byte packet) flags, it gets though with no problem
(1464 bytes + 28 byte icmp header = 1492 MTU)

So I’m not sure which is more accurate and why I’m getting this discrepancy.

Also I would like to note that without the router I do not have this problem.


Here are my test results at broadbandreports.com

MTU set in router options at 1492
http://ttester.broadbandreports.com/...ia=routerpppoe

MTU set in router options at 1400
http://ttester.broadbandreports.com/...ia=routerpppoe

Connected without WGT624v2 router using RASPPPoE
http://ttester.broadbandreports.com/...P&via=raspppoe

My test results at speedguide.net are pretty much the same


I’ve also connected my router to my brother in law’s Comcast cable and both sites say the MTU was 1500 just what it should be for cable internet.

So it seems that this is only a problem with PPPoE connections and this router, or maybe just a weird problem with this router and my isp.


I’ve also used a packet sniffer program and verified that the maximum tcp packet sizes being sent and received from my computer are 1452 bytes with the odd exception of icmp ping packets being at most 1492 bytes.


Also note that if I set my MTU on my computer though the registry to more than 40 bytes lower that what is set in the router config my these sites correctly say my MTU is what is set in the registry.


Anyways to recap my router is causing my MTU to be 40 bytes lower than whatever I set it at in the routers configuration.

Because a MTU of 1452 isn’t the most optimal and my router simply isn’t doing what I want it to I would like to get this fixed if possible.

If anyone here has any suggestions on how to fix this or have had this problem themselves with this router or any others for that matter I’d like to hear from you, because so far the post I made on netgears web forum hasn’t been productive.

My post on netgears forum
http://forum1.netgear.com/support/viewtopic.php?t=3500

[Andrzej]

patinsj welcome on SG Forum
it seems that is MTU stuck
the problem with PPPoE client in several Netgear routers
also yours : Netgear WGT624 v2
It is still remained UNSOLVED problem.
see thread MTU Size http://forums.speedguide.net/showthread.php?t=165238 link