Hi. I'm running enterprise linux version 3 WS, and trying to install cisco vpn client.
I have found several websites that allow download of cisco vpn client for linux without
any passwords or pins. However, upon running install, the installation is halted
at a point where it asks for the kernel source code to be installed. There appears
two brackets [ ] where the location of the kernel source code should be located,
but the brackets are always empty. I have tried to install 3 or 4 cisco vpn client
downloads, and they all get hung up at this point. I tried searching for the kernel
source but can't be sure if i've found it, or what to do with it once found.
I don't know the theory behind this...I am supposing the source code is the
non-binary version of the linux kernel that folks could hack to make new
distributions of linux, and is compiled to get it into binary form. But I don't
know what an "installation" of the kernel source code would mean, as opposed
to say a "compile". Also, I don't understand why the vpn client would need
the kernel source code, and also to have it "installed".
I have the 8 or 9 cd's for installing the linux, but don't know where the
kernel source would be on them.
Thanks for any help. Apologies if this same situation is on another thread.

You are correct, the software likely needs to be compilied against the kernel source code which is usually in /usr/src/linux if installed. The kernel sources are included on the installation CDs, though if you've updated through up2date, that source will not be the same as the current compiled kernel you're running. However, you can download the current kernel source directly from redhat (using up2date should work).

Thanks for the reply Cap'm. I don't think that i have changed the source in any way, and so it still should be the same as on the discs. There was no directory named /usr/src/linux that i could find on my machine. However, there was /usr/src/redhat, under which were the directories; BUILD RPMS SOURCES SPECS SRPMS. All of these looked empty except for RPMS, which contained the directories: athlon i386 i486 i586 i686 noarch, all of which looked empty. I wonder if i should re-install with the discs, or try to find the source on the discs. I wouldn't know where on the discs to find it though. If I were to find and download the source from the redhat site, would it be the same as my installed version? I still do not understand why cisco vpn client needs the source code, and i don't know what it means to "install the source code",...does that just mean to unzip it?
Thanks!

I don't think that i have changed the source in any way, and so it still should be the same as on the discs.
No, I meant if you've upgraded the kernel at all (like a security update) then the system will be using a different kernel version than the one originally installed on the system. If you haven't upgraded the kernel, then you really should as there have been several recent kernel vulnerabilities.

There was no directory named /usr/src/linux that i could find on my machine.
The kernel source is probably not installed then.

I wonder if i should re-install with the discs, or try to find the source on the discs.
Nah, assuming that you've registered with RHN, install the most recent kernel sources with:

up2date install kernel-source

this should download/dependency-resolve/install automatically for you. This will create the /usr/src/linux-2.4.21-20.EL directory for you.

If I were to find and download the source from the redhat site, would it be the same as my installed version?
If you have applied the security upgrades, then it should match your kernel version. If you haven't applied the updates, then you should do so immediately.

I still do not understand why cisco vpn client needs the source code
I don't know specifically, but I'm assuming that it requires kernel-specific settings in order to configure the VPN properly. In order to find these settings it has to look at the kernel source code. This is not that uncommon for networking related software.

and i don't know what it means to "install the source code"
If you use the up2date command, it will install the RPM for you. You could do the same manually by installing the RPM directly or by unzipping/untarring a gzipped-tarball kernel source, though you would still need to get it from RHN in order to remain supported by Redhat.