Martyn Drake wrote: The "modern" version is iptables and operates in a similar fashion to ipchains. Again, you'll need to make sure that your kernel has support for iptables enabled (whether it be as a module, in which case just try "modprobe ip_tables", or statically compiled into the kernel itself).
Thanks for your prompt reply to my question Martyn. I was unaware of the existence of iptables, but, on checking my system, I have discovered that I must have unknowingly installed it when installing Linux so it ready and waiting for use... Time for some experiments.
Ian.