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

From: Tom (anonymous_at_discussions.microsoft.com)
Date: 02/22/04 

Date: Sat, 21 Feb 2004 16:17:40 -0800

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.

Relevant Pages

  • RE: DHCP: not reached by clients
    ... Based on my research, we do not need to configure the DHCP or DNS on SBS, ... Run the Change Server IP address wizard to configure the SBS IP: ... One network adapter - manual router connection to broadband ... DHCP on router and other clients. ...
    (microsoft.public.windows.server.sbs)
  • Re: Simultaneous DSL and cable modem access on a SBS network...sorf ot.
    ... Internet Connection wizard on the SBS box, ... "More Information" button on what ports need to be opened to the SBS. ... The server and the fax (the line the DSL modem ... The cable modem already has a router attached to it as well, ...
    (microsoft.public.windows.server.sbs)
  • Re: Problem
    ... the remote site and see if they have the connection manager installed. ... So...whichever is easier to set up on the router. ... location B need to connect individually via VPN to the SBS server at ... server - not sure of the clients ip scheme - but I think it is ...
    (microsoft.public.windows.server.sbs)
  • Re: Open Ports
    ... want the ports open even ifs all in house and behind the hardware firewall??? ... it opens up in demo mode. ... server is Cisco Catalyst Express 500 switches for voice over IP. ... will take requests from the clients. ...
    (microsoft.public.windows.server.general)
  • Re: SBS 20003 R2 Newbie
    ... Try using a smarthost to send outbound mail from your SBS server. ... you may have better luck using the Earthlink ... In the router, you need to forward some ports to your SBS NIC: ...
    (microsoft.public.windows.server.sbs)
Loading