Re: Servers & Routers and Firewalls, Oh my....

From: Susan Bradley, CPA aka Ebitz - SBS Rocks [MVP] (sbradcpa_at_pacbell.net)
Date: 02/22/04 

Date: Sat, 21 Feb 2004 17:02:12 -0800

"(Don't ask, the boss didn't want to
spend money, but he will, I know when there is an
attack) "

Tom according to my read you have the potential of three firewalls.

1. That linksys is probably doing firewall duty
2. The SBS2k3 standard firewall that you disabled
and last and not least...

YOU BOUGHT ISA SERVER AND YOU AREN'T USING IT?

You SPENT money on a firewall dude USE THE DANG THING! Sorry but I'm
in one of those moods today where you guys should just say "yes dear"
and duck....

Turn the DHCP on the server, stop using it on the Linksys, check out the
network setups on www.smallbizserver.com Follow them as the "best
practices for securing your LAN.

Use what you have dude... you HAVE a firewall right under your NOSE!

Tom wrote:
> Hello,
>
> Ok, this might be a simple fix to others, but to me I
> just don't understand.
>
> Server:
> Cable modem comes in, connected to a Linksys Router, and
> then connected to NIC1 on SBS2003 Server. Then NIC2 is
> connected to a hub which all of the other workstations
> are connected to. Simple and normal.
>
> Problem:
> There is no firewall on the sever at all. We are using
> NAT translation. (Don't ask, the boss didn't want to
> spend money, but he will, I know when there is an
> attack) Anyway, for some reason the server is not
> allowing traffic through certain ports.
>
> Let me go into this a bit more. The router, which is
> connected to NIC1 is running DHCP so NIC1 can pull an IP
> from it. Which it did and it's working. The router has
> certain ports open and allowing traffic to the IP that
> the server pulled. In this case 192.168.20.100.
>
> Now, when clients try to use programs that needs those
> ports, it's acting like they are not open. The network
> is using 19.168.10.x as it's IP range. Under the old way
> when a server was not here, we would just open the ports
> for the specific client and pointed them to the IP of the
> client machine. So in theory, you would figure that
> since the Server is now acting as the gateway, you would
> point all the open [prts to the server and wa-la! IT
> should work and everything back to normal. Nope.
>
> But for some reason the server in the mix is now stopping
> the clients from seeing the ports as open.
>
> During the install of the SBS2003 software, we didn't add
> the ISA server, and during the Internet Setup we told the
> firewall to be disabled, so basically we are only working
> with what the Router has in the form of NAT translation.
> The ports needed are open, and pointing to the IP address
> reported in the DHCP list on the router. But thats odd
> as well. The router is saying 192.168.20.100 but the NIC
> in the server is reporting 192.168.20.102. This is
> stranger then strange.
>
> Why are these ports being seen as closed?!?!?!
>
> Thanks for any help you can offer, this one has me
> stumped...
>
> Tom.
> 

-- 
http://www.sbslinks.com/really.htm

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