> i d like to if it s possible to filter by hostname and not by ip address
> for iptables.
> the fact is that i want to administer my server from my machine at home
> which has a dynamic address (ADSL)
When building rules, you can specify a hostname rather than an IP. In
that case iptables converts the hostname to an IP via a lookup in the
local hosts file or DNS in order to build the internal representation of
the rule. And that's because all iptables sees is the source and
destination IP when a packet arrives.
Since you have a changing IP, the hostname associated with that IP (as
found in your provider's DNS) will change along with the IP. And it's
that hostname, not the one you have configured locally on your home
machine that matters.
You can do this relatively safely. In all likelyhood the IP that
you'll get on your ADSL connection is going to lie within a relatively
small range, probably a Class C address space. You could tell iptables to
allow ssh only from hosts in that range and then configure ssh to
restrict itself to those connections that offer the correct pre-shared
key or to restrict itself to connections from a particular user.
The instructions said to use Windows 98 or better, so I installed RedHat.