Enable/Disable TCP Auto Tuning

canspec

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Wondering what is best...Enable/Disable TCP Auto Tuning?:)
 

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Disable Windows Scaling heuristics
Windows Vista/7 has the ability to automatically change its own TCP Window auto-tuning behavior to a more conservative state regardless of any user settings. It is possible for Windows to override the autotuninlevel even after an user sets their custom TCP auto-tuning level. When that behavior occurs, the "netsh int tcp show global" command displays the following message:
** The above autotuninglevel setting is the result of Windows Scaling heuristics
overriding any local/policy configuration on at least one profile.
To prevent that behavior and enforce any user-set TCP Window auto-tunning level, you should execute the following command:
netsh int tcp set heuristics disabled
possible settings are: disabled,enabled,default (sets to the Windows default state)
recommended: disabled (to retain user-set auto-tuning level)
Note this should be executed in elevated command prompt (with admin priviledges) before setting the autotuninlevel in next section. If the command is accepted by the OS you will see an "Ok." on a new line.

TCP Auto-Tuning
To turn off the default RWIN auto tuning behavior, (in elevated command prompt) type:
netsh int tcp set global autotuninglevel=disabled
The default auto-tuning level is "normal", and the possible settings for the above command are:
disabled: uses a fixed value for the tcp receive window. Limits it to 64KB (limited at 65535).
highlyrestricted: allows the receive window to grow beyond its default value, very conservatively
restricted: somewhat restricted growth of the tcp receive window beyond its default value
normal: default value, allows the receive window to grow to accommodate most conditions
experimental: allows the receive window to grow to accommodate extreme scenarios (not recommended, it can degrade performance in common scenarios, only intended for research purposes. It enables RWIN values of over 16 MB)
Our recommendation: normal (unless you're experiencing problems).
If you're experiencing problems with your NAT router or SPI firewall, try the "restricted", "highlyrestricted", or even "disabled" state.
Notes:
- Reportedly, some older residential NAT routers with a SPI firewall may have problems with enabled tcp auto-tuning in it's "normal" state, resulting in slow speeds, packet loss, reduced network performance in general.
- auto-tuning also causes problems with really old routers that do not support TCP Windows scaling. See
MSKB 935400
- netsh set commands take effect immediately after executing, there is no need to reboot.
- sometimes when using "normal" mode and long lasting connections (p2p software / torrents), tcp windows can get very large and consume too much resources, if you're experiencing problems try a more conservative (restricted) setting.

If you're experiencing problems with Auto-Tuning, see also:
MS KB 835400 - email issues
MS KB 934430 - network connectivity behind firewall problems
MS KB 940646 - 3G WWAN throughput issues
MS KB 929868 - web browsing issues
MS KB 932170 - slow network file transfer
 

My Computer

Computer Manufacturer/Model Number
Gateway
OS
Win 7 Home Premium-64bit
CPU
2.3
Memory
4 gig
Try before to not allow ICMP in your firewall center => advanced parameters => IPsec Parameters, this will resolve some network connections problems if you don't need Icmp.

In registry editing:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
Value DWORD 32bits: EnableICMPRedirect set to "0"

This will be handy aswell to prevent an attack on Icmp, so it helps both "Connectivity & Security"


At the end of the MS KB934430 you've got a tool to test connectivity:
Internet Connectivity Evaluation Tool

This tool may help you in your request & your choices:)
Looks not manies have done what you're asking yet.


canspec, don't blame me i perfectly understand what you want...but every pc have their own way as broadband might not have all the same settings.
http://www.speedguide.net/read_articles.php?id=2574

I know speedguid.net since ages and they provide some usefull infos.
 
Last edited:

My Computer

Computer type
PC/Desktop
Computer Manufacturer/Model Number
Custom Build
OS
Windows 7 Professional SP1 - x64 [Non-UEFI Boot]
CPU
Ivy Bridge Core i5 3570K (Delidded)
Motherboard
Asus P8Z77-V LE PLUS
Memory
G.Skill "Ares" DDR3 PC3-12800 - 1600MHz (16Gb)
Graphics Card(s)
Asus Dual-RX480-O4G
Sound Card
Creative Sound Blaster Z w/5.1 sound system
Monitor(s) Displays
Asus IPS 23"
Screen Resolution
16/9
Hard Drives
Internal:
500Go Sata 6Gb/s (x2)
500Go Sata 3Gb/s (x2)
SSD 60Go Sata 6Gb/s
PSU
In Win C 900W Series 80+ Platinum
Case
Thermaltake Chaser A71
Cooling
Custom Water Cooling Loop
Keyboard
Cooler Master QuickFire XTi
Mouse
Razer Imperator 2012 (4G)
Antivirus
MSE
Browser
IE 11.0.xxx Rtm
Other Info
"Raid0" with Intel Smart Response Technology (HDD/SSD)
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