Quote:> Ok, My setup is one Linux Box(Mandrake) used as a simple file and
> print server for about 20 users. IP addresses are assigned via DHCP.
> This was a stand alone box but now we are getting DSL. The DSL company
> says they will issue me 5 static IP addresses. My IP Newbian questions
> are:
> How can I keep my DHCP going and still use this static IP to get the
> server online?
If by "20 users" you mean that you have 20 client computers, then 5
addresses is not sufficient *IF* you want all the clients to be directly
accessible from the Internet at large. The simplest configuration would
be to leave your local network configuration exactly as it is, with the
possible exception of adding a new or changed default route, and set up a
NAT router, which can be a ~$100 dedicated box, a new computer dedicated
to this purpose, or an existing computer that takes on this duty. This
system will be the default router for the network, and will use one
external IP address. All the other computers will "masquerade" behind
that one IP address. This approach works well for many small networks. A
similar approach is to not even use NAT, but this will restrict the
internal computers' access to the Internet. If you do this, you don't
really need five IP addresses; you just need one. If your ISP doesn't
offer a price break if you drop to a single IP address, you can just
leave four unused. If your ISP offers a lower price for a
single-IP-address account, though, you might want to consider changing
your order.
A variant on this approach is to give up to five computers their own IP
addresses on the Internet at large and to have the rest masquerade behind
a NAT router. Essentially, it'd look like this (ASCII art ahead; best
viewed in a monospaced fone):
+------------+ +-----------+
/| Exposed #1 | /| Hidden #1 |
/ +------------+ / +-----------+
/ /
/----------\ +--------+ / +------------+ / +-----------+
| Internet |---| Router |------| NAT Router |------| Hidden #2 |
\----------/ +--------+ \ +------------+ \ +-----------+
\ \
\ +------------+ \ +-----------+
\| Exposed #2 | \| Hidden #3 |
+------------+ +-----------+
In this setup, the NAT router is configured just as I described earlier.
The Exposed computers (and the NAT router) would be configured with your
ISP's static IP addresses, although you could use a DHCP server to deliver
those addresses to these computers. (This server could be on the Router,
on the NAT Router, or on some other system.) The advantage of this setup
is that the Hidden computers would be well protected against certain types
of attack, because they wouldn't be directly reachable from the Internet
(the NAT router blocks direct access attempts, while still permitting the
Hidden computers to initiate contact with other sites). The Exposed
computers could be used to run servers (web servers, etc.) or for those
rare user applications that have problems working through a NAT router;
but they'd be directly accessible to the entire Internet, which would make
them vulnerable to attack.
In either case, a Linux box can function as a NAT router, or you can buy
a standalone box to do the job. Even for a network of 20 computers, a
broadband router you buy at CompUSA or the like should be adequate, and
should be easy to set up. (You'd need extra switches or hubs, but you've
presumably already got those.)
Quote:> I have only 1 box, what am I to do with 5 static IP's?
It's unclear why you say you're using DHCP to assign IP addresses and
running file and print server software if you've only got one physical
computer. If you mean you only have one that's directly connected to the
Internet, then see above; you don't need five, but if that's just part of
the package you want for other reasons, leaving four of them unused won't
do any harm, except that you'll be consuming five (eight, really, as
Martin Cooper explained) IP addresses when you only need one.
Quote:> Am I going to have to install another ethernet card for these static
> Ip's?
It depends on how you set it all up. If you buy a separate NAT router and
put everything behind that router, then no, you shouldn't need more
NICs. If you want to turn an existing computer into a NAT router, then
the best approach is to use two NICs in it.
Quote:> If there any links or good books that can help me get an understanding
> I'll appreciate it...
Without knowing a bit more about your network, it's not clear to me
precisely what documentation would help you the most; however, I've got
information on several networking books (including some by me) at:
http://www.rodsbooks.com/books/books-network.html
Of course, the Linux Documentation Project is a free and often useful
resource. The documentation there is quite varied in topic, length, and
quality. Here's its URL:
http://en.tldp.org
--
http://www.rodsbooks.com
Author of books on Linux, FreeBSD, and networking
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