RE: Help me and my ISA server

From: Gallant, David (
Date: 06/10/02

Date: Mon, 10 Jun 2002 16:40:43 -0300
From: "Gallant, David" <>
To: <>

ISA requires 2 nic's to do its job connected to your
private network and the other connected to the public internet (or a

The LAT is used to determine how ISA routes internal requests. If the
IP address that is requested is within the LAT, it determines it to be
the private (internal) addresses (or local requests), anything else is
external and needs to be sent out. This helps in that the ISA does not
have to rely on a routing table to do its job, because even though ISA
routes's not a router. At no time should there be live
Internet addresses included in the LAT.

Once you have the second network card in, you create destination sets
and rules for inbound -> outbound requests for internal clients and
web/server publishing rules for outbound -> inbound requests from

ISA has many wizards to get you through.

Check out and the MS (ISA Server) newsgroups for extra
Both are great resources.


-----Original Message-----
From: Damien Ilmonen []
Sent: Monday, June 10, 2002 2:25 PM
Subject: RE: Help me and my ISA server

Yes, the LAT is only for people that are in your "private" space. If
you have everything in the LAT, than anyone who can access your IP
address can proxy off of your ISA server. Something that could be done
if you cannot change the physcial configuration is to enable user
authentication against the server so that only people logged into your
network can proxy off the server. However, I do not see why you cannot
add a second NIC to the ISA server, change the LAT, & modify the gateway
so that they using the ISA server. You'll be able to get better control
over your traffic & should be able to setup your content filtering and
any server hosting much better as well. You can't "publish" anything
when you only have one NIC in the ISA server.

Damien Ilmonen, CISSP

-----Original Message-----
From: []
Sent: Monday, June 10, 2002 7:03 AM
Subject: Help me and my ISA server

I've just got a job as a system administrator in one company which have
ISA 2000 server in it. When I look at the configuration of my isa server
I saw that it has only one network adapter connected to the public range
of IP adressess on my network. Internal client are comming from my
private range (192.168.x.x) through win2000 router 192.168.x.x /
194.x.x.x and comming to my ISA server one and only NIC 194.x.x.140.
Something like this /
194.X.X.139)------ISA(194.X.X.140)---------Zyxell (194.X.X.141)

I saw that lot of people use my ISA server as their proxy (people from
internet). I went to microsoft web site and saw that minimal
requirements for ISA 2000 (In integrated mode) are two network adapters
(one for private one for public). So I think LAT table in my case is
useless... Am I Right???? I want to know if this is real problem (My ISA
is exploited becouse of stupidity of an ex-administrator (guy before me
who installed ISA2000) Any help will be great and any questions or
suggestions will help me a lot. Thanks for your time and everything you
have allready done for me and my knowledge.

Milos K. V. , System Administrator
Belgrade, Yugoslavia

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