Need help with office wired LAN and WAP Internet

[Wiz Feinberg]

I posted a query about this last week but nobody replied, so I am rephrasing
the question in the hope that someone will understand what I am trying to do
and offer a solution that eludes me.

I am having a problem getting a small (5 machines) LAN to connect to both
the networked machines AND the Internet. Due to the use of Windows NT 4
Workstation on two very important machines, and Win XP on three new
computers, the network I am working on has to be statically configured for
all machines to communicate with each other. I cannot get any of these
statically assigned machines to connect to the Internet, whereas they do
connect instantly if they are set to Automatic IP Assignment, but loose
sight of the NT machines. The NT 4 machines do not need the Internet, just
LAN access to them (they are milling machines). The client would like to
have Internet access on the three XP machines, if possible, without loosing
the connection to the NT 4 machines.

I have tried configuring the NT machines to use auto IP, and listed the IP
address and subnet of the router/gateway, but they just go offline after a
reboot and must be reset to static IPs in the 192.168.1.x range, with no
default gateway. I have enabled NetBios over TCP on all machines, set
incremental IPs, in the range of 192.168.1.x, with the same subnet mask.
They all belong to the same Workgroup, have different machine and user
names, and are not on a Domain.

The Internet access comes from a T1 WAP feeding a D-Link 604 Router, which
has an internal fixed IP of 10.30.1.1, with a subnet of 255.255.255.0. It is
currently set to serve DHCP to the networked computers, with those addresses
all beginning with 10.30.1.x. Would turning off DHCP on the router get the
static IP (192.x.x.x) networked computers back online? Any other suggestions
would be appreciated that will allow both the LAN and the Internet.

 

[Kevin]

Sounds like there is a problem in the way you're hard
coding the DNS settings when you give them static
addresses. The fact that they can see the Internet when
running DHCP from the router tells me that there are no
Layer 1 problems.

When you say they "loose sight of the NT machines" do you
mean they can't log in? Or the NT machines don't even
respond to a Ping?

When you assign IP addresses statically, are you coding
those outside the DHCP range of the router?

What DNS value do you have plugged into the router... and
are you using that same value when you configure the
machines statically?

My recommendation would be to choose one or the other then
stick with it as you troubleshoot. Either use DHCP or
don't. That will help eliminate a lot of variables and
confusion.

Let us know how things go and we'll try to do our best.

 

[Wiz Feinberg]

Sounds like there is a problem in the way you're hard
coding the DNS settings when you give them static
addresses. The fact that they can see the Internet when
running DHCP from the router tells me that there are no
Layer 1 problems.

When you say they "loose sight of the NT machines" do you
mean they can't log in? Or the NT machines don't even
respond to a Ping?

When you assign IP addresses statically, are you coding
those outside the DHCP range of the router?

What DNS value do you have plugged into the router... and
are you using that same value when you configure the
machines statically?

My recommendation would be to choose one or the other then
stick with it as you troubleshoot. Either use DHCP or
don't. That will help eliminate a lot of variables and
confusion.

Let us know how things go and we'll try to do our best.

Kevin

Thanks for the reply. I am trying to work outside the IP range of the
router, so that must be where the trouble lies. I will be back on the job
later today and will try to force the NT machines to use IPs in the
10.30.1.x range, instead of the 192.168.1.x range that they are using now.

When the XP machines "loose sight" of the NT cutters they disappear from
Network Places and cannot be found by searching for a computer. Two of the
XP machines have high-end CAD programs that are supposed to feed coordinates
to the CNC cutters, over the network.

There is also another company also using the router and WAP, so I can't
disable its DHCP function, as I speculated in my post.

I will post back here when I have more info from today's tests.

 

[Wiz Feinberg]

I have resolved the networking problem myself. I looked carefully at the
TCP/IP settings properties for the NT computers and found that they both had
the MsLoopback Adapter installed and configured to use static 192.168.1.x
addresses, separate from the IP settings for the NICs. I changed only the
NIC IP addresses to automatic and left the loopback adapter settings alone.
Upon rebooting the CNC machines saw the DHCP assigned computers in the
workgroup. After changing all remaining machines to use auto DHCP from the
router, and leaving NetBios enabled over TCP/IP, every computer saw both
machines and connected to the Internet.

Thanks to Kevein for the question about the different IP ranges that got me
to think of the solution.