RE: ISA 2004 Design and Config

  • From: "Thomas W Shinder" <tshinder@xxxxxxxxxxx>
  • To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
  • Date: Sun, 26 Sep 2004 14:36:18 -0500

Hi Duncan,

Are you using:

Firewall client?
SecureNAT client?
Web Proxy client?

Remove the public DNS server from the external interface and put the
internal interface on the top of the interface list.

Create Access Rules allowing the traffic you want outbound. How would
you exert access control if a "hardware" firewall were installed? Just
let everything out?

HTH,


Tom
www.isaserver.org/shinder
Get the book!
Tom and Deb Shinder's Configuring ISA Server 2004
http://tinyurl.com/3xqb7
MVP -- ISA Firewalls



-----Original Message-----
From: duncan@xxxxxxxxxxxxxxxxxxxx [mailto:duncan@xxxxxxxxxxxxxxxxxxxx] 
Sent: Sunday, September 26, 2004 3:36 PM
To: [ISAserver.org Discussion List]
Subject: [isalist] ISA 2004 Design and Config


http://www.ISAserver.org

Can someone please give me some advice on the following,

I an currently working on a system upgrade for a client, the previous
domain was a Win NT4 Domain,

I started the upgrade on Friday this week, so far I have upgrade the
domain to 2003 AD, migrated all data,  migrated exchange 5.5 server to
exchange 2003, migrated SQL to SQL 2000, set up Citrix Meta frame XPa
farm.& MS SUS Server

All Server are HP ML370, 2gb, 3.06 Xeon

2 x 2003 Domain Controllers
1 x 2004 Exchange Server
1 x SQL 2000, on 2003 Server
1 x 2003 File Print
2 x 2003 Citrix Xpa Terminal Server
1 x 2003 SUS Server
1 x ISA 2004 running on 2003, 2nd NIC Installed,

Started to configure ISA today, I have never installed ISA before and am
having an absolute nightmare; I normally just install a Hardware
Firewall.

I am unsure how ISA should be. Configured 100%  I have web access
working
at the moment through the ISA Server but nslookups are failing
externaly,

Current config, 

ISA Server has two network cards, protected subnet is 192.168.x.x /24,
external card 172.29.x.x /24

External card has ISPs, DNS Servers, Internal Card has internal DNS
Servers, Internal card has no DG set, external card is connected to
protected interface on Hardware  FW 172.29.x.254,

Protected HWFW Interface then NATs out to Public IP, the current client
has a /29 block of IPs, so I have configured the next available IP as an
Alias on the HWFW, I then plan to setup the mobile VPN clients to that
IP
along with the site  to site VPNs when I start the satellite offices,

The protected network card of the ISA server is every host on the
subnets
default GW including all Servers

Internet traffic is working through ISA but if I try and do an external
nslookup the query fails, If I check the ISA logs I see messages, saying
DNS Closed or sometimes Denied,

NSlookups fail from every server including the ISA server I think the
only
reason http traffic working is due to the ISPs DNS Server being set on
the
external NIC,

I have tried taking the HW FW out of the equation but still have the
same
problem of DNS queries failing externally,

The only way I can think of getting this working for the client tomorrow
is to, set all the other servers DG to the protected interface of the
FW,
setup a separate DMZ on one of the other FW interfaces then connect  the
ISAs external card to the FW DMZ port,

I then plan to only allow port 53 out on the HW FW  protected Interface,
I
will then setup the protected interface on the HW FW to allow 2 way site
to site IKE VPNs from the other HW FWs in the satellite offices when the
come on line.

At the moment it setup so the protected FW interface is connected to the
second NIC of the ISA as a DMZ, with my new plan above the protected
interface on the FW will have a 192 address and will be connected to the
same switch as the server bypassing the ISA server

The Second card in the ISA will be connected to a separate DMZ and will
only be used for incoming smtp and outgoing http traffic

All web traffic from both PCs & Servers will go out through the ISA
Server,All PCs will have the ISA Server set as there DG Server will be
HW
FW

The hardware FW has a mail proxy  I want it  to send SMTP traffic to the
external card of the ISA server, then have it some how proxy to exchange
server. Can this be done ?

Can somebody please advice me the best practice for the installation I
am
trying to carry out as I am unsure of the best ways to setup ISA

Regards

Duncan Cameron

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