DOCBOOK: host/domainname/ip address

Hi,

I was wondering, as I come from a UNIX/Network background, if there are
any standard ways of representing hostnames, domainnames, and ip addresses
in DocBook.

I have no problem using them as arguments to commands but I was wondering
if phrase is a proper way of marking them up in descriptions or just plain
prose. Imagine describing a Domain structure as part of a Reference for a
firewall:

/.../
 You have the different internal int.donnellan.de domains which are
seperate to the donnellan.de domains and are seperate again to the
LDAP systems. Then there's foo-bar.donnellan.de and sol.donnellan.de which
both have different nameserver concepts. Sol has an internet aware
primary nameserver and acts as a go between for other DNS servers, and
then there's foo-bar which hosts a root nameserver for the ".", "de", and
donnellan.de domains. foo-bar plays host to the mail system and doesn't
care about the Internet as it passes all mail to a parent at 1.2.3.4.
/.../


Many thanks in advance...

	Sean

P.s. the above example bears no resemblance to any real firewall
documentation and is only an example of some "text" with domains and ips.