Disable Self-Tuning TCP

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Level 6

10,225 points

Disable Self-Tuning TCP

I need to disable this or, at the very least, take control of it. It's made doing anything on the internet a miserable, lengthy process. I had no trouble with Tiger and nothing but trouble with Leopard. It's throttling my downstream on both my Macs to useless levels.

If I can't disable or modify this I'm going to go back to Tiger to get things done. I own a business. I cant have this time wasting nonsense and I need a solution now. Much of my work is on the web. I'm paying for high speed access and getting low speed throughput.

The DNS settings are in place, no firewall setting improves this, I've reset all the Airports. Nothing changes. Downloading anything crawls to low speed but ONLY on the Macs.

Does anyone have a clue? Can I archive and install back to Tiger?

iMac G5 2.0 + MacBook 2.0, Mac OS X (10.5.1)

Posted on Nov 22, 2007 8:24 AM

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Answer 1

LarryHN

Level 10

106,142 points

Nov 22, 2007 8:30 AM in response to Ken.

The DNS settings are in place,

By this, do you mean that you have set static DNS servers instead of using DHCP for the DNS servers?

For many people simply turning off DHCP for DNS and setting several static DNS servers (preferably your ISPs local ones) have been a perfect work around for this

Larry Nebel

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Answer 2

Nov 22, 2007 8:46 AM in response to Ken.

This thread might help.

Worked Well here.

http://discussions.apple.com/thread.jspa?messageID=5662693&#5662693

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Answer 3

Nov 22, 2007 11:08 AM in response to Ken.

Add the following lines to /etc/sysctl.conf

kern.ipc.maxsockbuf=512000
net.inet.tcp.sendspace=131072
net.inet.tcp.recvspace=358400
net.inet.tcp.sockthreshold=0

Then reboot.

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Answer 4

Ken. Author

Level 6

10,225 points

Nov 22, 2007 1:30 PM in response to LarryHN

A significant but erratic improvement. The downstream speeds are closely to Tiger with DHCP off. Upstream may actually be a tick faster as well. We're on the right track.

Message was edited by: Ken.

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Answer 5

Ken. Author

Level 6

10,225 points

Nov 22, 2007 1:32 PM in response to ch0b1ts2600

This looks like the best answer but I'm concerned that it will be overwritten by the next update. I'll give it a shot.

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Answer 6

Ken. Author

Level 6

10,225 points

Nov 23, 2007 2:38 AM in response to LarryHN

This worked exactly once. On a reboot the Airport system would not come online at all. It doesn't particularly make sense since I entered the values manually. I booted to LInux to deal with the internet. What an ugly mess.

Message was edited by: Ken.

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Answer 7

Ken. Author

Level 6

10,225 points

Nov 23, 2007 8:01 AM in response to ch0b1ts2600

Strange. I don't have sysctl.conf, hidden, invisible or otherwise.

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Answer 8

LarryHN

Level 10

106,142 points

Nov 23, 2007 8:15 AM in response to Ken.

Try making the DNS change in the router and leaving the Mac to use DHCP - that is what I did and it works fine for me

Larry

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Answer 9

Ken. Author

Level 6

10,225 points

Nov 23, 2007 9:08 AM in response to LarryHN

Did that already. Speeds up for a bit then falls back.

This is extremely frustrating. This wasn't a problem in Tiger. It's not a problem with Linux, it's not a problem on the one PC on the network. It's only a problem with Leopard and on the two Macs I use for web work.

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Answer 10

Nov 23, 2007 10:23 AM in response to Ken.

That is indeed strange that you do not have one. If that is the case, then create sysctl.conf in /etc and add the following text.

kern.ipc.maxsockbuf=512000
net.inet.tcp.sendspace=131072
net.inet.tcp.recvspace=358400
net.inet.tcp.sockthreshold=0

After you save the file in /etc then make sure it has the proper ownership and permissions.

chown root:wheel /etc/sysctl.conf
chmod 0644 /etc/sysctl.conf

They will not be overwritten when you reboot and will be automatically loaded every time.

Message was edited by: ch0b1ts2600

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Answer 11

Ken. Author

Level 6

10,225 points

Nov 23, 2007 4:10 PM in response to ch0b1ts2600

That's what I thought. I can see invisible and hidden files and even used EasyFind to root it out. Nothing.

I'm in the middle of a project and will try this in a bit. It's a bit goofy to jump to another OS for internet.

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Answer 12

Ken. Author

Level 6

10,225 points

Nov 23, 2007 4:50 PM in response to ch0b1ts2600

Update: Either I'm completely blind or inept or sysctl.conf does not exist on my MacBook either. i'm in /etc and EasyFind doesn't pick it up either (set to show invisibles).

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Answer 13

Ken. Author

Level 6

10,225 points

Nov 25, 2007 4:27 AM in response to Ken.

I installed Apple's Broadband Tuner which created sysctl.conf. No lasting change. First test shows high speed and then it ramps down to a crawl on the second test.

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Answer 14

Nov 25, 2007 6:14 AM in response to Ken.

If you Option-click on the Airport icon in the menu bar what kind of speed are you getting?

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Answer 15

Ken. Author

Level 6

10,225 points

Nov 25, 2007 11:36 AM in response to Cardiakke

I'm showing 54, typical G band. Both Airports are set as G only. Noise is low. The range between stations and computers is less than 12 feet, signal strength is good. No nearby wireless systems on my channel.

Reading through my ISP's logs I've had connections as fast as 10.2+mbps, with the rare drop to 9. Now I'm lucky to hold onto 7, which drops to 3. Only the first download is fast. It gets progressively slower as time goes on until I reboot.

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