mtu/rwin

Sebby · Sep 20, 2009, 00:52:45

DrTCP is definitely fine to use with XP.

drummer · Sep 20, 2009, 02:57:00

Maybe I'm going senile, but I think the 1500 MTU recommendation came from experienced forum members, rather than IDNet itself.

TCP Optimizer was also very popular at the time because it actually worked. It also allowed users to change their mind if the recommended options didn't work for them.

I've been using 1500 MTU on the router and all OSs for over two years now and it's never been a problem.

kinmel · Sep 20, 2009, 07:14:51

Quote from: drummer on Sep 20, 2009, 02:57:00
Maybe I'm going senile, but I think the 1500 MTU recommendation came from experienced forum members, rather than IDNet itself.

TCP Optimizer was also very popular at the time because it actually worked. It also allowed users to change their mind if the recommended options didn't work for them.

I've been using 1500 MTU on the router and all OSs for over two years now and it's never been a problem.

You are right, it was all self inflicted and 1500 did prove to be best setting for my ADSL line.

TCP still recommends that I use 1500

Gary · Sep 20, 2009, 08:54:05

having done the ping -f -l 1472 bbc.co.uk test and decreased by 10 untill I do not get get "packet needs to be fragmented" then increased by 1 each time until I am 1 away from that, then added 28 I get 1458 for my MTU, which has lowered my Pings and increased the loading speed of most sites so 1458 is the correct MTU for my line

Steve · Sep 20, 2009, 09:22:52

Tried again myself using DG834N, the wired/wireless Windows machines have no fragmentation at 1472 on my line (if its reporting correctly) I did make the mistake of testing with the router initially set at MTU 1458 and ended being down to about 1435 before the fragmentation stopped. So I think I'll leave it wide open for the present.

Haven't tried on the Macs as I don't know the command

Bill · Sep 20, 2009, 10:51:04

Quote from: stevethegas on Sep 20, 2009, 09:22:52
Haven't tried on the Macs as I don't know the command

I think it's ping -D -s xxxx host (eg ping -D -s 1472 bbc.co.uk) but I'm on an unfamiliar setup here so can't be 100% certain.

That's assuming I've read the info from "man ping" correctly.

Gary · Sep 20, 2009, 14:08:47

Quote from: stevethegas on Sep 20, 2009, 09:22:52
Tried again myself using DG834N, the wired/wireless Windows machines have no fragmentation at 1472 on my line (if its reporting correctly) I did make the mistake of testing with the router initially set at MTU 1458 and ended being down to about 1435 before the fragmentation stopped. So I think I'll leave it wide open for the present.

Haven't tried on the Macs as I don't know the command

I made the same mistake Steve, and 1500 is right for my line, no fragmentation at 1472 either.

LesD · Sep 20, 2009, 16:36:26

Quote from: sobranie on Sep 19, 2009, 22:30:03

Would sfc /scannow reset things in general do you think Les?

I am not familiar with that command I am afraid maybe a Google for it would turn something up.

Despite what I pointed on on the link I posted I am sure Dr TCP worked OK for me in XP so I am sure Sebby is right.

As I recall the Speedguide site never seemed to agree with what I belived I had set though.

Here in Vista as it "Ain't Broke" with my router MTU at 1500 and the Vista default, whatever it is, I am not going to try fixing it!

Especially as I have just obtained this at the Command prompt with no fragmentation:

Microsoft Windows [Version 6.0.6002]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\Les>ping -f -l 1472 bbc.co.uk

Pinging bbc.co.uk [212.58.224.138] with 1472 bytes of data:
Reply from 212.58.224.138: bytes=1472 time=63ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=60ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=61ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=62ms TTL=122

Ping statistics for 212.58.224.138:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 60ms, Maximum = 63ms, Average = 61ms

C:\Users\Les>

LesD · Sep 20, 2009, 18:14:59

I have had a Google myself for sfc /scannowand found this.

Since it would appear that the MTU is a registry setting I don't think restoring files to their original state would reset the Windows MTU unless anyone knows better that is.

Lance · Sep 20, 2009, 18:42:08

I don't think vista has a default, but instead adjusts dynamically as needed.

Gary · Sep 20, 2009, 19:51:26

Quote from: Lance on Sep 20, 2009, 18:42:08
I don't think vista has a default, but instead adjusts dynamically as needed.

Its meant to but the MTU seems to stay at 1500 if yo type netsh interface ipv4 show subinterfaces into a cmd window and you will see what the settings are, when I changed my Router to 1458 and rebooted Vista did not chage the MTU it remained at 1500

Sebby · Sep 20, 2009, 22:15:47

Quote from: Lance on Sep 20, 2009, 18:42:08
I don't think vista has a default, but instead adjusts dynamically as needed.

That's my understanding, Lance - I remember looking into it when I used Vista. That said, I believe there's a way to make it static and change the value.

Lance · Sep 21, 2009, 06:34:09

I'm sure your right, Sebby, as I remember doing it myself!

wecpcs · Sep 21, 2009, 12:22:11

Quote from: LesD on Sep 18, 2009, 21:45:13
I thought so too until I saw reply #8 here!

After reading that comment from Simon at Idnet, I tried changing mine from 1500 to 1458 and my ping times almost doubled to 76 from a normal 41 and my download speed dropped by half from around 7Mb to 3.5Mb. I immediately changed back to an MTU setting of 1500 on my Netgear DG834G v4 and everything is back to normal again. I will not try that again in a hurry.

Colin

sobranie · Sep 21, 2009, 14:12:28

I wonder if IDNet would swop my almost new V5 for a V4.

Sebby · Sep 21, 2009, 19:31:01

There's only one way to find out, but I'd say probably not.