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Cant change back to an MTU of 1500

N/A

Cant change back to an MTU of 1500

My knowledge of networking is minimal but I thought I'd play around with the settings for maximum throughput. I downloaded DrTCP and changed the settings to those suggested on the 'Tweaking thread'. Checking them on dslreports.com suggested they weren't optimal for me and I altered the RWIN to the highest multiple of MSS in the range they thought best.

After rebooting things seemed better except that they now suggest an MTU of 1500. So I changed that and rebooted but it made no difference and MTU seems permanently stuck on 1472 (Which is 40 bytes more than MSS).

Can someone explain why I can't change back to 1500?
4 REPLIES
pcorker
Grafter
Posts: 309
Registered: 05-09-2007

Cant change back to an MTU of 1500

If you are using the Binatone 3 lights modem this seems to only allow a max value of 1472, Don't know why or if there is a way of changing that.
The sticky thread at the top of this forum will give some pairs to try (note warnings about very low RCWINs there and elsewhere)
Pat.
N/A

Cant change back to an MTU of 1500

If you've loaded and Saved Blank/default values
with DrTCP then youv'e restored MTU to 1500 on
Your PC.
However as stated above, your modem is setting MTU to
1472 so you won't be able to go above this value.
You maybe getting the message to set MTU back to
1500 on DSLreports because you have ticked the
'normal' box instead of 'PPPOA' which is your connection
type.
Alec
N/A

Cant change back to an MTU of 1500

Thanks for the replies. I am indeed using the Binatone 3 light modem and I had left it on normal connection. I'm at a different pc now away from home but If I recall correctly the rwin I've set is 12,888. This is a multiple of 9 times MSS.

Another thing that is odd is that DrTCP shows me having three network adapters. One is an unused network card but the two others are both Binatone modems. The second is shown as #2 (Installation didn't go smoothly and I installed twice is my guess as to why).

I've only had adsl for about a week and I'm very pleased with the downloads I get (45k+) but although webbrowsing is faster its not as fast as I thought it might be. There seems to be a delay sometimes in DNS lookup and then the page appears. I notice I have several unused network protocols. Could my browser be searching these firstly before DNS? If I try nslookup everything appears almost instantaneously. Any advice on my setup would be appreciated.

My pc is a 2400+ 256mb adsl500 using ie 6
N/A

Cant change back to an MTU of 1500

It may be worth uninstalling the drivers via hardware-
device manager, re-booting and re-installing or start by
removing one, check which is in use and enabled.
You may aswell set MTU with DrTCP to same value as
modem.
If using IE6 try the Microsoft patch posted here by
tffive also the link (in my post) to the registry tweaks on the Cablenut site will provide a boost in surfing speed.
Also worth checking your using the correct DNS servers,
212.159.13.49 & 212.159.13.50, run the command ipconfig/all.
The slowdown may be a temporary thing not connected to your
set-up , also worth checking is your Exchange status
Alec