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16. The Optimizer does not tweak my MTU correctly ?

If you tweaked your Registry settings in the TCP Optimizer, however our online Analyzer still shows a lower MTU value, there is probably something on the line that limits your MTU. It could be software on your PC (such as AOL / Compuserve, PPPoE software), a broadband router, or your ISP.

The Analyzer actually looks at packets transferred between you and our server. Such packets are also limited by other routers on the path, while the Optimizer only tweaks your PC.

Here are some troubleshooting tips:
First, make sure that the Analyzer detects your external IP address correctly (not some proxy server).
Also, make sure your router is updated with the latest firmware, and check its Web-based management interface for a specific MTU setting you can adjust.
Note if you're on a PPPoE/PPPoA connection, the maximum packet size (MTU) can not exceed 1492.
You might want to try bypassing your router temporarily, to determine whether it is affecting your MTU value (by connecting your machine to the modem directly). Note you should reboot the modem every time you connect a different device to it.

Ultimately, if your ISP, or router are limiting your MTU, you can still simply tweak the rest of the settings using your particular MTU value. The exact MTU size has minor impact on throughput.

  User Reviews/Comments:
by ace_ventura2 - 2008-01-31 04:38

This is the result of the analyser TCP Analyzer Results
Tested on: 01.31.2008 04:32
IP address:

TCP options string: 020405b40103030201010402
MSS: 1460
MTU: 1500
TCP Window: 256960 (multiple of MSS)
RWIN Scaling: 2
Unscaled RWIN : 64240
Reccomended RWINs: 64240, 128480, 256960, 513920
BDP limit (200ms): 10278kbps (1285KBytes/s)
BDP limit (500ms): 4111kbps (514KBytes/s)
MTU Discovery: ON
TTL: 47
Timestamps: OFF
IP ToS: 00000000 (0)

Can U kindly tell me if everything is fine ? I am getting very low download speeds (between 1.50kbytes to max 10kby)

Any help would be much much appreciated. My email id is

by maximusdecimus - 2008-04-02 04:18
hi ive dowloaded the TCP optimizer and changed the settings as is my info.

but still i do not see any increase in speed unlike others who claim ave had tremondous speed gains..pls help me outt will b very grateful to ya...
thnx... TCP Analyzer Results
Tested on: 04.02.2008 04:05
IP address: 59.96.xx.xx

TCP options string: 020405a00103030401010402
MSS: 1440
MTU: 1480
TCP Window: 1028160 (multiple of MSS)
RWIN Scaling: 4
Unscaled RWIN : 64260
Reccomended RWINs: 63360, 126720, 253440, 506880
BDP limit (200ms): 41126kbps (5141KBytes/s)
BDP limit (500ms): 16451kbps (2056KBytes/s)
MTU Discovery: ON
TTL: 43
Timestamps: OFF
IP ToS: 00000000 (0)
by Philip - 2008-04-02 08:00
Please use the forums for questions and help with the Optimizer/Analyzer:
by maximusdecimus - 2008-04-03 08:56
hope id meet ya there:)
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