How to know if two physical networks will not conflict with each other on my computer?

  • Thread starter Thread starter Dmitry Kopnichev
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Dmitry Kopnichev

Hello
How to know if two physical networks will not conflict with each other on my
computer? I would like to connect the two networks to two NICs in my Windows
2000 computer. Our former domain administrators installed two Win2k
computers for a person, one for each networks. They connected the systems to
the same keyboard, mouse and monitor. One of the networks gives an internet
access to me. How to make Default Gateway a gateway that takes me to the
Internet and assign it on the proper interface? Both networks require IP
address and address of DNS-server are got automatically in TCP/IP
properties.
 
Make sure that routing is not configured on your computer if you do not want
it to act like a router. The command ipconfig /all will show if routing is
enabled or not. There can only be one default gateway used on the computer
at one time and it should not matter what adapter it is configured on. The
other consideration is the priority you give to network adapters as shown in
network connections advanced/advanced settings -connections. The one at the
top of the list is the one that is used for DHCP, dns, etc. --- Steve
 
Thanks for your helpful reply.
The routing is not enabled. Only one NI card is installed yet.
Is a default gateway used for connecting to Internet. If yes, then should it
be configured on the adapter, which is connected to the one of our networks
with Internet access?
Which network adapter should be at the top of the list in network
connections advanced/advanced settings -connections, the adapter connected
to our LAN with Internet access or the adapter connected to our isolated
internal LAN?
 
It should not matter which adapter you configure the default gateway on as
long as that network connection is enabled on your computer. The default
gateway is needed for internet access. You should be able to ping your
default gateway and also ping or tracert internet addresses such as
Yahoo.com. It is hard to say which adapter should be at the top of the list
in your situation and it may not matter that much but normally that would be
the adapter that accesses your internal dns and wins servers and domain
controllers if your computer is in an Active Directory domain. --- Steve
 
If the default gateway is needed for internet access, should I configure an
adapter connected to a LAN with Internet access (not to a LAN with access to
our internal resources) the default gateway?
How to make sure that my computer is in an Active Directory domain?
How to know which of my two LANs has or both of them have internal dns and
wins servers and domain controllers?
 
You could configure the default gateway on the adapter that is connected to
the lan with the internet access. If your computer is a member of a domain
it will show that when you look at system properties - computer name and
look to see if it is a member of a domain or workgroup. If it is a domain
member then you want the adapter at the top of the list to be on the network
where the domain controller is for that domain. If it is a workgroup it does
not really matter. You should know that there is a risk in connecting a
computer to two networks. If the computer gets a virus or worm, that virus
or worm could spread to any network that the computer is connected to and
may be the reason that separate computers were used before to keep the
networks isolated from each other for security reasons. --- Steve
 
Yes, my computer is a member of a domain. My Windows 2000 appears to log
into the same domain with the same credentials with any of the LANs
connected to the one NIC. How to know in what network the domain controller
is for that domain?
Windows Autoupdate is enabled, all updates are installed as soon as they
appear. Mcafee VirusScan 8.0.0 is updated and VirusScan 8.0.0 on-access scan
is enabled.
 
How to make sure that routing will not be configured on my computer after
installing the second NIC?
 
The command using the support netdiag /v will show info about the domain
controllers and I believe it will show the IP addresses otherwise try to
ping a domain controller by name or use the command nslookup and then enter
the domain controllers fully qualified domain name to find it's IP address.
Domain computers should only use domain controllers as their preferred dns
servers as shown by the command ipconfig /all and as explained in the link
below. If netdiag is not on the server install the support tools from the
install disk in the support/tools folder.

http://support.microsoft.com/default.aspx?scid=kb;en-us;291382

It is wonderful that you are using MacAfee VirusScan 8.0.0 on your computer
but that is no guarantee that it will not get a worm or virus that is not
yet in the definition file that the program uses. Also a "hacked" computer
could also be a threat to any network connected to a computer. You will have
to make the final decision on whether the risk is worth it or not as in is
saving the cost of another computer more important than the data on your
isolated network and what would a worse case scenario cost if the isolated
network was infected by a worm and shut down and possible loss, theft, or
corruption of data. --- Steve
 
You have to configure it via the tcp/ip properties of the network adapter or
by adding it to the DHCP scope used by the network adapter if the computer
uses DHCP. You can use the command ipconfig /all to see if you currently
have a default gateway. To manually add a default gateway to an adapter you
need to manually configure a static IP address and subnet for that
dapter. --- Steve
 
It should not be enabled by default. You can verify that with the command
ipconfig /all. For Windows 2000 Pro their is a registry setting that
controls the computer being used as a router as shown below. --- Steve

To disable IP routing

1 .From the Start menu, click Run.

2.Type regedt32.exe or regedit.exe, and then click OK.

3.In a registry editor, navigate to
HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\Tcpip \Parameters

4. Select the "IPEnableRouter" entry (by defining as value : 0 ) :
 
ipconfig /all shows that DHCP is allowed, a default gateway is the same
172.31.144.1 and DHCP server is the same 172.31.0.10 for the both NICs,
IP-routing is turned off.
I successfully installed the second NIC - TRENDnet MEDIAnet USB To Fast
Ethernet Adapter TU-ET100C. First 10 minutes I could get access to network
resources through it, but now any of the two networks, connected to it, is
not accessible. Both networks are accessible through first NIC
interchangeably. I unchecked "Register addresses of this connection in DNS"
in both NICs properties.
How to get access to a network through TU-ET100C NIC?
 
Thanks Steve.
Yes, my computer uses DHCP. How to add the default gateway to the DHCP scope
used by the network adapter?
 
Thanks Steven.
I pinged domain name shown on Network Identification tab of My computer
properties. The ping showed an address for the domain name. ipconfig /all
showed this IP address as a DNS-server for a first NIC connected to
internal, without Internet access LA network.
I entered nslookup, then the IP address for the domain name, and the command
showed
Server: name.(domain name shown on Network Identification tab)
Address: a second IP address
ipconfig /all showed this second IP address as a DNS-server for a second NIC
connected to a LAN with Internet access.
Is this a right configuration?
 
netdiag /v shows 5 DCs, one of which is down, and IP addresses for only two
of them. My domain computer uses a domain controller and another IP address
as its preferred dns servers as shown by the command ipconfig /all for both
NICs.
How to know in which of the two LANs the 5 DCs are?
 
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