[sclug] OT: Android 1.5 TCP options ordering bug

Alex Butcher lug at assursys.co.uk
Tue Feb 2 08:21:10 UTC 2010

Hi Martin -

On Tue, 2 Feb 2010, Martin Summers wrote:

> Clutching at straws here - is there a tool (similar to iptables ?)
> which you can use to strip out some of your TCP options  and make it a
> bit more "compliant" ?

Great minds! That was one of the things I googled last night - to see if
netfilter has TCP options rewriting/normalisation. I couldn't find anything.
That'd certainly work for home, but it's dirtier than NAT/PAT. :-)

> The only other thing I can think of is either proxying to another local
> device (useless when you are mobile I guess), or if there is some tool
> that allows you to tunnel services over UDP (again, its all manual build
> stuff I guess).

That'd get the browser working, but there doesn't seem to be a generic SOCKS
system-wide proxy setting.

Also, as you note, it'll only fix the problem when I'm on my home network. 
Elsewhere, where I have no control over the devices on-path to the Internet
hosts I wish to connect to, I may well get no connectivity at all, or some
netblocks/sites/hosts may be effectively blackholed. The right answer is to
upgrade to Android 2.0 and with it, kernel 2.6.29; I'm hoping T-Mobile can
give me a pre-release.

> How painful is it to try a different Kernel

It's possible but it's somewhat involved -
<http://forum.xda-developers.com/showthread.php?t=572683>. I'd also be a bit
concerned about warranty, and bricking a 12 hour old device.

> - or is it easier and cheaper to replace the Zyxel router ?  Out of
> curiosity, how widespread have you found the router intollerance to be
> when "out and about" using the device mobile ?

?40-ish for a new router. No idea how many intolerant devices there are out
there. When Linus commented on the bug, he reckoned devices should be
tolerant of what 2.6.27's IP stack did, but reversed the change for the sake
of interoperability, which suggests it's a significant problem, at least
with consumer kit.

> I guess the other option is to just wait and see what upgrades are
> released......(waiting costs you money in the mobile handset game !)

Yup! As I understand it, HTC released Android 2.0 ages ago, but T-Mobile are
farting around with it, adding branding and so on.

> Regards,
> Martin
> P.S My Zaurus c860 is still serving me well ;-)


I swear it's all getting worse. I saw a tweet from one of the Laurie
brothers saying that his Honda car was recalled for a firmware bug recently.
Does nobody test things anymore? Oh, I forgot, that's what customers are


More information about the Sclug mailing list