I did a test using CMD, not sure if it helps

C:\Documents and Settings\>ping google.com -f -l 1400

Pinging google.com [173.194.41.130] with 1400 bytes of data:

Reply from 173.194.41.130: bytes=1400 time=29ms TTL=58
Reply from 173.194.41.130: bytes=1400 time=29ms TTL=58
Reply from 173.194.41.130: bytes=1400 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1400 time=30ms TTL=58

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 29ms, Maximum = 30ms, Average = 29ms

C:\Documents and Settings\>ping google.com -f -l 1472

Pinging google.com [173.194.41.130] with 1472 bytes of data:

Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\>ping google.com -f -l 1462

Pinging google.com [173.194.41.131] with 1462 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 173.194.41.131:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

There is no MTU in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tcpip\parameters\

Thanks

C:\Documents and Settings\>ping google.com -f -l 1440

Pinging google.com [173.194.41.130] with 1440 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\>ping google.com -f -l 1435

Pinging google.com [173.194.41.130] with 1435 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\d>ping google.com -f -l 1432

Pinging google.com [173.194.41.130] with 1432 bytes of data:

Reply from 173.194.41.130: bytes=1432 time=29ms TTL=58
Reply from 173.194.41.130: bytes=1432 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1432 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1432 time=29ms TTL=58

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 29ms, Maximum = 30ms, Average = 29ms

C:\Documents and Settings\RS Parkin Ltd>ping google.com -f -l 1433

Pinging google.com [173.194.41.130] with 1433 bytes of data:

Reply from 173.194.41.130: bytes=1433 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1433 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1433 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1433 time=30ms TTL=58

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 30ms, Maximum = 30ms, Average = 30ms

C:\Documents and Settings\RS Parkin Ltd>ping google.com -f -l 1434

Pinging google.com [173.194.41.130] with 1434 bytes of data:

Reply from 173.194.41.130: bytes=1434 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1434 time=29ms TTL=58
Reply from 173.194.41.130: bytes=1434 time=30ms TTL=58
Reply from 173.194.41.130: bytes=1434 time=30ms TTL=58

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 29ms, Maximum = 30ms, Average = 29ms

C:\Documents and Settings\>ping google.com -f -l 1435

Pinging google.com [173.194.41.130] with 1435 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 173.194.41.130:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

So we have 1434 + 28 = 1462?

In reply to a post by XRaySpeX:

In reply to a post by MHC:

Can you check it on the XP machines?

@OP: This is how: see Working out your maximum MTU for each XP PC.

And how does that help in finding out what the MTU is actually set to?

Can you get a copy of DrTCP and run it. That will show the MTU for each interface on the PC - you can then set it to 1492 if you need to.


MTU was only a thought, I know that if I set mine to a low value the upstream speeds will drop off.

In reply to a post by ScottPk:

So we have 1434 + 28 = 1462?

Yes. the MTU setting of that PC seems to be too low at 1462.

However, I'm surprised at the 'Request timed out.' response. It should be 'Packet needs to be fragmented but DF set.'.

Can you retry with the target_name at end as specified, just in case, and use bbc.co.uk, as recommended, rather than goggle.com? I expect the trip to the States is hindering you.

You may test it manually the quick & dirty way I pointed you at or you may automate it using an application. It makes no odds; it amounts to the same thing. Whichever you are happier with.

In reply to a post by ScottPk:

There is no MTU in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tcpip\parameters\

It'll be on some of the
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tcpip\parameters\Interfaces\xxxxxxx
or else there is something fishy going on.

Used DrTCP to change MTU from default (No Value in DrTCP) to 1492. Did a speedtest. Exactly the same, 25mbps download, 0.01mbps upload.

Then I did a Ping to bbc.co.uk

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\>ping bbc.co.uk -f -l 1464

Pinging bbc.co.uk [212.58.244.20] with 1464 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 212.58.244.20:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\>ping bbc.co.uk

Pinging bbc.co.uk [212.58.244.20] with 32 bytes of data:

Reply from 212.58.244.20: bytes=32 time=19ms TTL=56
Reply from 212.58.244.20: bytes=32 time=19ms TTL=56
Reply from 212.58.244.20: bytes=32 time=18ms TTL=56
Reply from 212.58.244.20: bytes=32 time=19ms TTL=56

Ping statistics for 212.58.244.20:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 18ms, Maximum = 19ms, Average = 18ms

C:\Documents and Settings\>ping bbc.co.uk -f -l 1434

Pinging bbc.co.uk [212.58.244.20] with 1434 bytes of data:

Reply from 212.58.244.20: bytes=1434 time=22ms TTL=56
Reply from 212.58.244.20: bytes=1434 time=22ms TTL=56
Reply from 212.58.244.20: bytes=1434 time=22ms TTL=56
Reply from 212.58.244.20: bytes=1434 time=22ms TTL=56

Ping statistics for 212.58.244.20:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 22ms, Average = 22ms

C:\Documents and Settings\>ping bbc.co.uk -f -l 1435

Pinging bbc.co.uk [212.58.244.20] with 1435 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 212.58.244.20:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
________________________________

There are some strange things going on, but I do not know what.

My connection has dropped about 10 times this morning, with a few minutes of blackout, then it just comes back on.

Thanks for all your help so far!

Well, something's preventing it going above MTU = 1434 + 28 = 1462, but I still don't like those time-outs. I get 'Packet needs to be fragmented but DF set.' every time and I'm on XP.

What could be the cause of it?

Shall I try on my Laptop instead?

Thanks

Scott

In reply to a post by ScottPk:

What could be the cause of it?

Shall I try on my Laptop instead?

Thanks

Scott

may give more insight

http://www.elifulkerson.com/projects/mturoute.php

A recent update of MSC caused problems with windows xp systems (freezing/slow). Assume MsMpEng.exe does not appear now in services.msc
What have you replaced MSE with?

http://www.techienews.co.uk/979984/microsoft-securit...

Edited by flippery (Wed 07-May-14 22:32:39)