+ Post New Thread
Results 1 to 5 of 5
Windows Thread, What is the DHCP router when you have an ISA2004? in Technical; Before we installed our ISA2004 box, DHCP used to give out the IP address of the router as the Router ...
  1. #1
    eejit's Avatar
    Join Date
    Jun 2005
    Location
    Ireland
    Posts
    606
    Thank Post
    52
    Thanked 12 Times in 12 Posts
    Rep Power
    22

    What is the DHCP router when you have an ISA2004?

    Before we installed our ISA2004 box, DHCP used to give out the IP address of the router as the Router option. Now that we've installed the ISA we've set the LAN ip address of that as the router/gateway. Is that how everyone else does it?

    Everything does seem to work under that setup, but if you do a "netdiag" from anywhere, you get the "[FATAL] NO GATEWAYS ARE REACHABLE" message. I guess that may not be a problem, but I'm just looking for some 'best practice' advice I guess.

    Thanks.

  2. #2
    eejit's Avatar
    Join Date
    Jun 2005
    Location
    Ireland
    Posts
    606
    Thank Post
    52
    Thanked 12 Times in 12 Posts
    Rep Power
    22

    Re: What is the DHCP router when you have an ISA2004?

    What do you guys set as your DHCP gateway? Is the router's LAN the correct thing to do?

  3. #3
    ChrisH's Avatar
    Join Date
    Jun 2005
    Location
    East Lancs
    Posts
    5,009
    Thank Post
    120
    Thanked 282 Times in 260 Posts
    Rep Power
    108

    Re: What is the DHCP router when you have an ISA2004?

    My Linux Box has 2 cards one in the range of the cisco router in the 10.X.X.X range and one for my local lan range 192.X.X.X . The clients are pointed the 192.X.X.X range.
    The Linux box has one gateway which is the router in the range 10.X.X.X .

  4. #4

    Join Date
    Oct 2005
    Location
    Kent and London
    Posts
    13
    Thank Post
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0

    Re: What is the DHCP router when you have an ISA2004?

    This is easy to answer with pictures, but I'll stick to words for now!

    The default gateway is the address of the device that knows how to get places not on the LAN, in most cases the firewall or internet router.

    I am assuming that you have a single LAN - no routers on your internal network!

    Before you had a proxy server, each workstation would have accessed the internet directly to get web pages. This means it needed to know how to get to the router, which would have sent packets on to the right place.

    With a web proxy, each PC only needs to know how to get to the proxy server, which is on the LAN so that is easy. The proxy server is then the only server that needs to know about the outside world, so it will need an accurate default gateway set.

    In other words, if all services use a proxy server, then the default gateway on PCs on the LAN is not relevant, so can be blank or wrong!

    Of course, you can use ISA server as a router, firewall and/or proxy so setups can get a lot more complicated!

    Note you also need to have DNS proxied somewhere for things to still work, but that would be pretty standard setup (your internal DNS server will be a DNS forwarder)

    (NB - a better design is to have the proxy in a DMZ, so there is a firewall between the LAN and the proxy, and again between the proxy and the outside world. However, removing the direct link between internal machines and the internet is a GOOD THING)

    Hope that helps!

  5. #5

    Ric_'s Avatar
    Join Date
    Jun 2005
    Location
    London
    Posts
    7,596
    Thank Post
    109
    Thanked 764 Times in 595 Posts
    Rep Power
    181

    Re: What is the DHCP router when you have an ISA2004?

    Indeed a pic is the best way to describe the setup.

    For a simple installation:
    * Set the ISA server LAN-side NIC as the gateway
    * Add your upstream proxy details (where appropriate)
    * Remember to setup the HTTP rules! (For testing you can open all protocols but do NOT forget to tighten up again!)
    Attached Images Attached Images

SHARE:
+ Post New Thread

Similar Threads

  1. Replies: 1
    Last Post: 17th January 2011, 02:36 PM
  2. DHCP handing out wrong router IP
    By SimpleSi in forum Wireless Networks
    Replies: 3
    Last Post: 27th September 2007, 10:00 PM
  3. what router?
    By browolf in forum Wireless Networks
    Replies: 15
    Last Post: 21st September 2007, 10:25 AM
  4. Wireless router
    By LukeC in forum General Chat
    Replies: 17
    Last Post: 5th July 2007, 06:07 PM
  5. snmp on isa2004
    By browolf in forum Windows
    Replies: 1
    Last Post: 11th May 2006, 09:26 AM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •