cancel
Showing results for 
Search instead for 
Did you mean: 

MTU Value / DrTCP

N/A

MTU Value / DrTCP

I heard a lot of people are having better speeds once they changed the MTU, how do i actually use this DrTCP program? What values do i use for Plusnet?

Or is there a registry entry i can add/edit for it?

Thanks for any help in advance Smiley
22 REPLIES
basils57
Dabbler
Posts: 18
Registered: 31-07-2007

RE: MTU Value / DrTCP

I was Just about to ask the same question - to the uninitiated it seems confusing.
Can someone please explain what to do in a pratt's guide?


--
N/A

RE: MTU Value / DrTCP

> I heard a lot of people are having better speeds once they changed the MTU, how do i actually use this DrTCP program? What values do i use for Plusnet?
>
> Or is there a registry entry i can add/edit for it?
>
> Thanks for any help in advance Smiley

I use {easy mtu}to set mine but find [receive window ]and [ file cache]size make setting up most trouble
N/A

RE: MTU Value / DrTCP

When you use Dr Tcp, it will list all your current network interfaces and the current MTU setting for each.

If you have only one network interface such as a usb router this will be listed in my case its an ethernet router

Select the network interface that is your connection to the internet and in the box next to it marked MAX MTU enter 1458, its probably currently set to the 1500 default at the moment.
Hit the Apply button and then shutdown and restart your PC.

After Reboot

Goto the following site www.speedguide.net then goto their TCP analyzer page and this will tell you your current MTU setting and other details as well, if it isnt 1458 then repeat the above procedure until it takes.

Hope this is of help

Good Luck

Ali
N/A

RE: MTU Value / DrTCP

Once you have succesfully managed to change your MTU, using the procedure in my last post you should try changing your Tcp Receive Window setting using DrTcp and repeat the procedure i outlined above.

The TCP receive window should be set to a value of 14180

Good luck again

Ali
N/A

RE: MTU Value / DrTCP

This next stage is only for users who have more than one internet connection and use Internet Connection Sharing (ICS).

Open DrTcp select the network adapter that is connected to your local network (LAN) and modify its settings to match your network adapter connected to the Internet.

Apply the changes and reboot

And thats it your all done

All this info and more is available in the Dr TCP faq over at www.dslreports.com
Check it out its good reading for new users.

Ali
N/A

RE: MTU Value / DrTCP

Go to www.ds;reports.com/tweaks and run the tweaktester utility.

Once run, proceed to the next page and fill out the type of connection that you have.

On completion you will see what the optimum settings are for your system.

You can then change them using drtcp.exe.

If anyone wants a copy of drtcp then you can email me.

Best Regards,

Dave Watson.

--
| David Watson. Unmetered & ADSL solutions
| Technical Support. for Home & Business
| PlusNet Technologies Ltd. @ http://www.plus.net
+ ----- My Referrals - It pays to recommend PlusNet ----- +
N/A

RE: MTU Value / DrTCP

> Go to www.ds;reports.com/tweaks and run the tweaktester utility.
>
> Once run, proceed to the next page and fill out the type of connection that you have.
>
> On completion you will see what the optimum settings are for your system.
>
> You can then change them using drtcp.exe.
>
> If anyone wants a copy of drtcp then you can email me.
>
> Best Regards,
>
> Dave Watson.
>
> --
> | David Watson. Unmetered & ADSL solutions
> | Technical Support. for Home & Business
> | PlusNet Technologies Ltd. @ http://www.plus.net
> + ----- My Referrals - It pays to recommend PlusNet ----- +


Look at that example, Plusnet customer support is excellent in my opinion Smiley
N/A

RE: MTU Value / DrTCP

>>
> Look at that example, Plusnet customer support is excellent in my opinion Smiley


Thank you. We
try our best.

Best Regards,

Dave.


--
| David Watson. Unmetered & ADSL solutions
| Technical Support. for Home & Business
| PlusNet Technologies Ltd. @ http://www.plus.net
+ ----- My Referrals - It pays to recommend PlusNet ----- +

N/A

RE: MTU Value / DrTCP

Just one other point I have previously set the MTU to 1458 when my upload speed fell a week as so ago. This worked fine and none of my packets were fragmenting.

I rechecked yesterday as the connection seemed sluggish and I found I was getting packet fragmentation. Dropping the MTU down to 1430 solved it.

Remember you are setting the MTU to avoid fragmentation of data packets and you should check what that value is before setting it in DrTCP. If you type the following ping into your dos window you will see if you are getting packet fragmentation at an MTU of 1458. If you are then change the value to 1430 and then see.

ping -f -l 1458 www.google.co.uk

Whichever value avoids fragmentation enter this into DrTCP.
N/A

RE: MTU Value / DrTCP

When I run Dr FTP, it doesn't show an MTU setting for my PCI ADSL modem (supplied by PlusNet). Should I still enter 1458? I'm sure I've read elsewhere that the MTU setting should only be changed for USB modems, so does it apply to PCI modems as well?

Also, the page Dave mentioned:

http://www.dslreports.com/tweaks

says that RWIN should be set to a maximum of 13140, yet Ali in a post above says to set it to 14180. Therefore, there seems to be a lot of conflicting advice around. Is there a *definitive* source of information for all this stuff? Is it OK to go along with whatever the above website says (and it doesn't recommend changing the MTU setting, to me at least)?
N/A

RE: MTU Value / DrTCP

> When I run Dr FTP, it doesn't show an MTU setting for my PCI ADSL modem (supplied by PlusNet). Should I still enter 1458? I'm sure I've read elsewhere that the MTU setting should only be changed for USB modems, so does it apply to PCI modems as well?
>
> Also, the page Dave mentioned:
>
> http://www.dslreports.com/tweaks
>
> says that RWIN should be set to a maximum of 13140, yet Ali in a post above says to set it to 14180. Therefore, there seems to be a lot of conflicting advice around. Is there a *definitive* source of information for all this stuff? Is it OK to go along with whatever the above website says (and it doesn't recommend changing the MTU setting, to me at least)?

Chris

I initially set my MTU to 1458 and Recieve window to 14180.

After the changes over the weekend everything seemed a bit slower so ran the ping test as detailed above and found I was fragmenting.

Have now set the MTU to 1430 and Recieve window to 13140 and all seems to be running ok.

hope this helps

Steve
N/A

RE: MTU Value / DrTCP

> Remember you are setting the MTU to avoid fragmentation of data packets and you should check what that value is before setting it in DrTCP. If you type the following ping into your dos window you will see if you are getting packet fragmentation at an MTU of 1458. If you are then change the value to 1430 and then see.
>
> ping -f -l 1458 www.google.co.uk

The ICMP header takes 28 bytes, so the MTU should be set to the highest value that works with ping plus 28.
N/A

RE: MTU Value / DrTCP

> I initially set my MTU to 1458 and Recieve window to 14180.
>
> After the changes over the weekend everything seemed a bit slower so ran the ping test as detailed above and found I was fragmenting.
>
> Have now set the MTU to 1430 and Recieve window to 13140 and all seems to be running ok.
>
> hope this helps

Thanks for the info, Steve. Do you have a PCI modem?
N/A

RE: MTU Value / DrTCP


When you first run DrTCP the entry is blank (well it was when I ran it). The MTU entry you are changing is a setting in the registry that windows sets as a default to 1500 for broadband and 576 for dailup connections. DrTCP is just an easy way to change this entry without editing the registry. Go to www.dslreports.com/faq/tweaks for FAQ on this.

The settings Steve H has suggested work fine but try some changes yourself to the RWIN you may get an improvement for your setup (there is a RWIN calculator at dslreports). You set the MTU value as the largest value that does not fragment data packets and you get that by pinging as shown in message above. Just try it, as you can always change it back if you want. Remember you must reboot after making changes and I suggest you go back to tweak tester to check the MTU has changed as it took two reboots for the setting to take for me(don't know why?).