Hi I use Debian testing and before and including kernel 2.6.26-2-amd64 I had no problems. After upgrading the kernel through 2.6.27 to the latest one 2.6.32-trunk-amd64 the following problems have occurred:

1 Eclipse (all versions) cannot access the network/internet) error is "Network is unreachable". As a result you cannot install or update any eclipse software.

2. I cannot access mysql database using the mysql-connector-java. No connection is made to the database.

3. In java applications the Date control gives the wrong dates in applications.

I reinstalled kernel 2.6.26 that came with the stable version. When I boot 2.6.26 all the problems go away. When I boot any kernel later than 2.6.26 the problems occur on the same Debian amd64 machine.
What has changed in the kernel, how can I fix it, is a bug. Every version since 2.6.26-2 gives these problems.
Any help or similar problems would be appreciated.
Thanks,
Rob Key

Hi I managed to fix this problem as follows:
1. Installed the source for linux-source-2.6.32

2. Used the config from the prebuilt kernel 2.6.26-2-amd64

3. did make silentoldconfig. Chose defaults for all new options.

4. Installed the kernel and headers.

5. Booted the kernel and all problems go away.

6. Eclipse can connect to all software sites, my applications can connect to mysql databases. No problems.

My new question is which option has changed in the pre-built kernels and surely others must be experiencing these same problems with the pre-built kernels post 2.6.26?
Thanks,
Robert Key

One way to find out would be to do a diff on the config files.

Evo2.

1 members found this post helpful.

Hi yes this is what I did but there are at least 20 differences. One of them was sysfs was turned on in the pre-built kernel and off in the custom kernel. But it was not this option. I will find out which option is the problem. I will post it when I find it.

Just takes time!
Rob Key

I have discovered (after a month) the debian kernel has ipv6 support build into the kernel. If one changes this to a module, all the problems are solved. Eclipse can update software and communicate. There are no java or mysql problems at all. I guess I should post this on a kernel forum somewere.
Rob Key

Hi,

I think you can work around this problem without recompiling the kernel by setting the parameter at runtime. For example I have file called: /etc/sysctl.d/bindv6only.conf that contains:
Cheers,

Evo2.

Thanks very much. I usually do compile my kernel in any case to make it as small as possible. But setting the kernel option makes things much easier. I wonder why the ipv6 built into the kernel causes problems? I did look a the bugs for that kernel version and there was mention of ipv6 having broken code.
Thanks,
Rob

As I understand it, it is not a kernel bug. The problem is cause by the fact (IMNSHO) that java sucks big hairy ones.

Cheers,

Evo2.

I did try net.ipv6.bindv6only = 0 with the new kernel 2.6.32-3-amd64 but it made no difference. I built a new kernel from source with all the ipv6 stuff as modules and this also would not work. I then built a kernel with no ipv6 stuff in it and it worked! This is all for 2.6.32-3. I would like to use lenny but the versions are just so old and it does not support ext4 file systems which I use. Yep it is time consuming.
cheers,
Rob

Did you reboot? If youd don't reboot you need to set it manually with:
Evo2.

I did reboot, I know that it is effectively a kernel command line option. It made not difference to eclipse. Eclipse could not "test connection". The only way is to recompile (2.6.32-3) and remove the ipv6 network code, then it works. Even if ipv6 is all modules in 2.6.32-3 it does not work. However ipv6 modules in 2.6.32-trunk does work. Interesting difference.
Rob