LG Revolution won't tether since Gingerbread upgrade

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Which device (manufacturer, type)?
LG Revolution
Which firmware is installed?
2.3.4 Gingerbread
What version of wireless tether are you using?
3.1-beta11 And tried many previous versions too.
What steps will reproduce the problem?
1.
2.
3.

What is the expected output? What do you see instead?

Please provide any additional information below.
Was running successfully on 2.2.2, upgraded to 2.3.4 Gingerbread, re-rooted. 
Now no web browsing works using any combination of device type and connection 
type. MSS Clamping is missing as an option since upgrade to version 2.3.4. That 
was the magic ticket with Froyo 2.2.2.

Original issue reported on code.google.com by itsav...@gmail.com on 14 Jan 2012 at 2:47

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Interesting note, I installed "Open Garden Wifi Tether" from the market on this 
same phone and it tethers perfectly on LG Revolution running 2.3.4.

Original comment by itsav...@gmail.com on 14 Jan 2012 at 4:18

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Additional notes: Tried at home where only 3G is available, including lowering 
MTU on the wifi adapter, but browsing to the internet by wifi tether devices 
fails. Used the exact same equipment and settings 45 minute drive away in a 
nearby city with 4G coverage and it worked correctly on both 4G and 3G 
connections. So the things that have changed since it worked. Was running 
android 2.2.2 changed to 2.3.4. since on 2.3.4 and the lastest (or any lower 
rev.) of android-wifi-tether. Now works on one cell tower, but fails on 
another. Also, I noticed Open Garden Wifi Tether behaves the same way.

Original comment by itsav...@gmail.com on 18 Jan 2012 at 10:38

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Did more testing.
From home I ran PDANet on 3G network. Worked perfectly.

Switched to Wifi Router, ran the following command from a tether PC, altering 
the packet size until the correct max size 

was found.
ping www.yahoo.com -f -l 1400

So the correct MTU is 1400 + 28 (header size) = 1428, which happens to be the 
same as on the 3G radio. (bond1)

used gscripts lite to modify the MTU settings on Revo wifi adapter, wl0.1 to 
reduce MTU down to 1428
ip link set dev wl0.1 mtu 1428

verified setting
ip addr show | grep wl0.1
ip addr show | grep bond1:

Both show as 1428

Connected Win7 64 laptop, but browser still did not work, although pings up to 
1400 bytes does work.

Then I made the following changes to my laptop:
netsh interface ipv4 set subinterface "Wireless Network Connection" mtu=1428

(Described in detail here: 
http://www.richard-slater.co.uk/archives/2009/10/23/change-your-mtu-under-vista-
or-windows-7/ )

Everything worked during tether session.

I set the MTU on the Revo back to 1500 and reconnected to Laptop. Still worked.
Tomorrow I will check the MTU size in the nearby city to see if the connection 
is different from the one near my home, I suspect it will be 1500.

This is leading me to believe the lack of MSS Clamping in the Revo gingerbread 
2.3.4 version is, in fact, the problem here. Additionally, it would seem that 
Windows 7 does not automatically adjust MTU to that of the connected wifi 
access point.

So I'm wondering if MSS clamping could be built into the wifi router code?

Original comment by itsav...@gmail.com on 19 Jan 2012 at 6:41

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Think I'll add one more test result tonight. I changed the laptop back to MTU 
1500, and changed the Revo wifi router settings, Enabling "Routing Fix" and 
"Wifi-driver reload".

I was excited to find that some website could now be be accessed. I turned the 
two settings back off and the number of websites went down again.

So now I suspect that some web servers (or routers between my laptop and the 
web servers) are set to enforce MTU 1500 and not allow packet fragmentation, 
while others are less strict. This further confirms the need for MSS clamping 
functionality to be created within the wifi tether app.

Original comment by itsav...@gmail.com on 19 Jan 2012 at 7:18

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So a couple more test results.
In the 4G coverage area I turned off the 4G LTE radio (rebooted) and ran 
tethering. Same results as at home, a few small websites worked 
(www.myflexonline.com) but google.com and most others would not connect, unless 
I set the MTU of the connecting (tethered) system manually to 1428.

Turned the 4G LTE radio back on and everything worked without the MTU 1428 on 
the tethered device, even if it supposedly left the 4G and lowered the 
connection speed to 3G network.

Seems the problem remains that 3G MTU on Revo Gingerbread requires MSS 
Clamping, which is not handled in either the OS kernel, nor in 
android-wifi-tether application. I guess I'll be going back to Froyo for now 
and accept that I don't really need the front facing camera to work.

If anyone figures out how to make this work, please respond.

Original comment by itsav...@gmail.com on 19 Jan 2012 at 9:25

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The app checks if "CONFIG_NETFILTER_XT_TARGET_TCPMSS" is compiled into the 
kernel. If not "MSS Clamping" is removed from settings.

Check /proc/config.gz on you device (pull it from your device, unpack it and 
open it in a text-editor) and you will see that this option is missing.

The get that option shown-up install a kernel which has this feature 
compiled-in. 

Original comment by harald....@gmail.com on 19 Jan 2012 at 11:37

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Do you already know of a Gingerbread release that has the 
"CONFIG_NETFILTER_XT_TARGET_TCPMSS" is compiled into the kernel for LG 
Revolution? Or have a recommendation where to look? Do you know if Ice Cream 
Sandwich has it included?

Original comment by itsav...@gmail.com on 20 Jan 2012 at 1:40

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Alternatively, have you considered building an MSS Clamping function into the 
app itself?

Original comment by itsav...@gmail.com on 20 Jan 2012 at 1:41

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Well I finally decided to swich back to Froyo on the device, the wifi tether is 
more important than th front facing camera to me.

Original comment by itsav...@gmail.com on 7 Feb 2012 at 6:09