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Date:      Mon, 23 Oct 2000 04:24:56 -0600 (CST)
From:      Ryan Thompson <ryan@sasknow.com>
To:        "Bilti, Roland" <RolandBilti@TI.SLR.com>
Cc:        "'freebsd-questions@freebsd.org'" <freebsd-questions@FreeBSD.ORG>
Subject:   Re: help
Message-ID:  <Pine.BSF.4.21.0010230406340.62267-100000@ren.sasknow.com>
In-Reply-To: <F198F82AE687D411BB7900062938A14D132E45@timexch01>

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Bilti, Roland wrote to 'freebsd-questions@freebsd.org':

> 
> > Hi,
> > 
> > I have an server 5x86 133MHz, 16 ram and I intend to use freebsd to give
> > internet access to 30 clients (under win95) . The server have 4 network
> > adapters( I use 4 adapters because we want to do this in a campus for 4
> > etajes). I checked the documentation available on www.freebsd.org  but I
> > need some detailed instruction because I am a  beginner. Please send me an
> > email with some documentation for firewall rules and to  give access to
> > internet with 4 network adapters.

Check out the O'Reilly book "Networking with TCP/IP".  If you can't find
it locally, I can fetch the ISBN, publication info, etc for you.  It
explains the processes, and many of the UNIX-centric procedures for
configuring networks.  Surf the local (or online) bookstores for other
networking titles.  You will want to read up on firewalls, too..  FreeBSD
comes with ipfw(8) in the base system, and that works for me... but you're
not limited to that.  There are other packages out there.  As far as
firewall rules are concerned, look at /etc/rc.firewall for an example, and
read ipfw(8) for syntax explanations.

What are "etajes"?  I am not familiar with the term.

In short, you may not need 4 network adapters, but assuming you do, you
will need to assign each network adapter a distinct subnet in your address
space (or assign local addresses to each).  If the subnets are on
non-octet boundaries (smaller than /24), you'll definitely want to read
about classless subnetting before attempting anything.

One of the network adapters will have to talk to your Internet uplink
(i.e., router).  Thus, your default route must go through one of the
adapters, to the uplink device's IP address, which should be on the same
subnet as the network adapter in question.  Call that network adapter 1.

You could have other hosts connected to the Ethernet of network adapter 1.  
(You already have two, the FreeBSD machine, and the router).  In this
configuration, this Ethernet is referred to as the DMZ (demilitarized
zone), as it is NOT protected by your FreeBSD gateway/firewall for
Internet access.  It is common to put some DNS or mail servers in the DMZ.

The other three network adapters should be placed on three different
Ethernets.  Your FreeBSD machine should provide routes to three different
(non-overlapping!) subnets.

So, your FreeBSD machine will be a gateway for all four subnets, and can
act as a firewall, proxy, etc, for all four subnets.  You better use good
hardware for your FreeBSD machine and have backups/replacements available,
as it now represents a single point of failure in your network design.

You will need to enable IPDIVERT and IPFIREWALL in your kernel.  Enabling
4 or so bpf's is almost a requirement nowadays.  I'd also recommend
increasing MAXUSERS a bit, depending on what sort of servers you plan to
run, and how much traffic you expect to flow through this machine.  If the
system is JUST going to be a gateway/firewall, and logs are exported to a
log server, you could probably get by with very small disk partitions.

Ok... That's enough on networking fundamentals, for now ;-)  Once you
decide on your network architecture, and formulate some specific FreeBSD
related questions, we can help you out with specific troubles.


> > Thank you in avans,
> > 
> >  Rolland
> 
> 
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-questions" in the body of the message
> 

-- 
  Ryan Thompson <ryan@sasknow.com>
  Network Administrator, Accounts
  Phone: +1 (306) 664-1161

  SaskNow Technologies     http://www.sasknow.com
  #106-380 3120 8th St E   Saskatoon, SK  S7H 0W2



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