Sometimes, users find some web sites not opening,and
try all tweaks, including Formatting the disk.!
Now check here first.

http://www.isup.me/

If web site is functional, mention the modem/details here
in this forum for suggestions. or try MTU change.

Usually changing MTU value in your modem/router suggested.
( most modems/routers have this option usually in WAN page )

General instruction for finding your optimal MTU size
000:
Go to Start and select Run.
Start RUN
Type in cmd (Windows 2000/XP/Vista/7) or
command (Windows 98/ME) into the box .
Hit the enter key or click OK
001:
At the DOS prompt,
type in: ping bbc.co.uk -f -l 1492
(*or the web site not accessed say http://www.yahoomail.com)
and hit the Enter key.

002:
If you get the response "Packet needs to be fragmented but DF set",
lower the size the packet in increments of +/-10 (e.g. 1472, 1462, 1440, 1400)
until you have a packet size that does not fragment.

Now increase the packet size from this number in small increments until you
find the largest size that does not fragment.
003;
Add 28 to that number (IP/ICMP headers) to get the optimal MTU setting.
For example, if the largest packet size from ping tests is 1462, add 28 to
1462 to get a total of 1490 which is the optimal MTU setting and can be put
in your router's settings
!
Hope this helps some of you!?

Source : NETGEAR site.

004:
Applications:
You can try application DRTCP
or Sg Tcpoptimizer from http://speedguide.net.

Quite useful

Another reference explaining in detail.
http://blog.wisefaq.com/2009/09/01/dete ... ould-care/

Applications:

http://www.dslreports.com/front/DRTCP021.exe



http://www.speedguide.net/downloads.php

Test:
In computer:
START run type cmd Ok
new window
type [color="red"] ping http://www.google.com -f -l 1492


Setting MTU size

is a process of trial-and-error: start with the maximum value of 1500, then reduce
the size until the problem goes away. Using one of these values
is likely to solve problems caused by MTU size:

1500. The largest Ethernet packet size; it is also the default value.
This is the typical setting for non-PPPoE, non-VPN connections.
The default value for NETGEAR routers, adapters and switches.

[color="blue"]1492. The size PPPoE prefers[/color].

1472. Maximum size to use for pinging. (Bigger packets are fragmented.)

1468. The size DHCP prefers.


1460. Usable by AOL if you don't have large email attachments, etc.
1430. The size VPN and PPTP prefer.

1400. Maximum size for AOL DSL.

source NETGEAR:

Hi,
Thanks for the informative share mate.It is very useful for others too.

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