I'm a Linux newb running Mandriva 10.1 on two older machines, mostly for learning purposes. I'm able to access the internet fine with both of them, both were installed using FTP. On either of those two boxes, I'm able to ping my Windows XP SP 2 machine and even use rdesktop to remote desktop into XP. I'm now trying to use VNC to connect to the linux machines (although I'm a few steps away from that). Right now, I can't even ping the Linux machines. (and they can't ping each other). I've tried completely shutting off shorewall and restarting networking services but still without any luck.

The computers are all setup on the same LAN.

Reading different threads around here, I tried to ping localhost (127.0.0.1) and realized that I can't, which makes me suspect that something is in fact wrong.

One last thing. One of the computers is really old and I can't seem to get the GUI's to work. Not that I'm complaining, the whole point of having these machines is for me to learn the command line rather than just GUI stuff. So if anyone can help me and be specific with command line methods, that would be great.

Is this a problem with Mandrake or am I just missing some settings. I'm getting annoyed and thinking about trying out SUSE or Red Hat.

Try looking at your firewall settings, maybe you have the ping protocol blocked in and out.

Well, like I said, it didn't even work when the firewall was completely off. Anyway, here's whats in /etc/shorewall/rules (at least part of it):
Do I need more there?

ACCEPT net fw icmp 8 -

I thought it might be of use to note that I can't ping (on either machine) by name (localhost) or ip (127.0.0.1)

What isn't instantly discoverable, is that if you select level 5 security (called "higher", IIRC), then there are a set of settings applied which block activities. At install, it is suggested as a sensible option, but I struggled to grasp the implications of the setting, and how to selectively release some of the settings. This is not just done by not loading or starting some services, but a fairly sophisticated set of configurations and services are applied.

So for example all the internet services are blocked from remote servers, and some services, like ping, are blocked altogether.

Unfortunately, you have to know that there is a thing called msec (Mandriva(ehem!) Security) that does a couple of things:

- automatically reverts some changes (it was driving me mad that my permanent password setting didn't stick)
- uses a DENY ALL in the configuration files for internet services from remote services.

So for example SSH does not work even though it is all correctly configured (or rather only works locally, which rather defeats the point). After many happy hours restarting and rebooting, downloading new versions of puTTY and getting not one single useful error message aside from server unexpectedly disconnected the light dawned that there was another configuration file at work and an entry in hosts.allow solved the problem.

(Not the most comprehensive answer, but I last Linuxed at Redhat 7.2 and its all been a little distressing porting across!).

It would be useful to find a good link with some examples on how to get level 5 slackened off safely.