RE: firewall setup

["David Gillett" <gillettdavid () fhda edu>]

  Yes, sort of, although that's only one way to do it.

  You would have the firewall performing NAT (Network Address Translation)
between public and private addresses.  For each of these servers, you'd
put in a static NAT rule mapping the server's public IP address to a new
private address where the server actually resides.

  Another common alternative is to install the firewall as a router or
bridge
(only a few firewall products can act as bridges, but this often simplifies
introduction of the new firewall to an existing network) between the
servers (perhaps the entire campus network) and the rest of the world.  With
any luck, the servers may be able to keep their current addresses.

  In order to use the firewall's address as you describe, there are a couple
of additional issues:

1.  The "firewall" may be acting as a "reverse proxy".  Microsoft's ISA
server can do this, and it's actually a pretty good approach to take.

2.  The firewall may be doing "port forwarding".  This is really a SOHO-type
feature, popular with sites who only have one public address.  It pretty
much
requires that any particular service (web, email, etc) only be hosted by one
server because the firewall has no way to know which box a given URL should
refer to.

David Gillett
(at a big .edu)


> -----Original Message-----
> From: Ognen Duzlevski [mailto:maketo () sdf lonestar org]
> Sent: Wednesday, July 07, 2004 7:33 AM
> To: securityfocus
> Subject: firewall setup
>
>
> Hi, I have a basic question:
>
> we have several boxes with unique public IP addresses which
> are part of a
> big .edu namespace. I would like to put these machines behind
> one single
> firewall and still keep their names. Is it possible to have all names
> point to the firewall machine and then have the firewall direct the
> specific request to a specific box behind it?
>
> So, if F is firewall.x.edu and I have A.x.edu, B.x.edu and
> C.x.edu I want
> to have A, B and C behind F. A, B and C should now point to F
> and F will
> direct all outside requests to A, B or C based on the name.
>
> Thanks,
> Ognen
>
>
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