Networks

Ask something
Discussion Locked

Routing Problem?

0 helpful
19 replies

by wayne r.

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

We need to change all of our IP addresses on the entire network; before my time our network was created using non-standard numbering (130.1.0.0 don't ask why, no-one knows!) and I now wish to recreate it using the 10. private address structure.

I've installed a temporary 2K server to act as a router between the ranges, it has two NICs one with an IP in the 130. range, the other with an IP in the 10. range, it is configured to route IP traffic between subnets, although they are physically on the same network.

I have given all of our servers a secondary IP address in the 10. range.

I have assigned a workstation with a 10. IP address and it can quite happily ping any computer on the 130. range and also all of the 10. addresses on theservers. That's as far as it goes though, I can't browse or connect to resources on any of the 130. machines or even the servers with the secondary 10. addresses.

I've changed the default gateway on the 10. workstation to the 10. address on the 2K router, the 130. address on the 2K router and also the 130. and 10. addresses on the original default gateway.

I've probably missed something glaringly obvious but I've started going around in circles looking for the problem now.

Any ideas? Please let me know if you want more info than I have provided above.

Cheers,
Wayne.

19 replies

by maelgwyn

Ok, have you checked the route tables?

But something; why dont you implement a DHCP server, and make ALL the machines (bar servers, of course) get the new address range? That way, the roll out will take, a bootup rather than ages (as with manualaddressing), and you wont have that problem no longer...

Now, I cant see a flaw in your logic, so is the servers sharing correctly across your router (duh its not), so I think it could be something wrong with the router, or with the IPs of the server. I cant be 100% sure without being there.

Maelgwyn

by wayne r.

Hi, the routing table of the 2K box:

Active Routes:
0.0.0.0 0.0.0.0 130.1.1.12 130.1.2.40
10.16.32.0 255.255.254.0 10.16.32.31 10.16.32.31
10.16.32.31 255.255.255.255 127.0.0.1 127.0.0.1
10.255.255.255 255.255.255.255 10.16.32.31 10.16.32.31
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1
130.1.0.0 255.255.0.0 130.1.2.40 130.1.2.40
130.1.2.40 255.255.255.255 127.0.0.1 127.0.0.1
130.1.255.255 255.255.255.255 130.1.2.40 130.1.2.40
224.0.0.0 224.0.0.0 10.16.32.31 10.16.32.31
224.0.0.0 224.0.0.0 130.1.2.40 130.1.2.40
255.255.255.255 255.255.255.255 130.1.2.40 130.1.2.40
Default Gateway: 130.1.1.12

I've already installed DHCP for the 130. range and enabled DHCP for the machines that don't need to remain static. I've also created a new scope for my 10. range but have not yet enabled it. The trouble is we have three remote offices and doing the change in 'one hit' is not feasible, that's why I need to get the routing working.

Thanks for taking the time to answer though.

by tech010

Do you have a Wins server, or are the systems both part of the same workgroup? Sounds like a name resolution issue.

by wayne r.

All machines are members of the same domain. We do have a WINS server and it currently has two IPs' allocated to it the primary from the 130. range and the secondary from the 10. range.

by mshultz

This may be a little stupid of an idea but.. Is it possible that when you ping a computer on the 130 range that you are actually pinging a server/host on the internet? You said that the 130 range is public so it's possible that the internet router is just letting it through.

If you kill the internet connection and try accessing something in the 130 range, you'll know.

by wayne r.

The 130 range is definitely local, if I do ping -a it returns the local host name. Also, external pinging is blocked at the firewall.

Thanks anyway.

by wayne r.

Hi, I've read the article and it's pretty much just confirmed what I have already learned without offering anything new. I installed RRAS a few days ago to enable IP forwarding, I couldn't ping between the ranges until I had done this.

Thanks anyway.

by armylanman

Whoa.. Back up here..

To tell what is going on we need a better picture of what network infrastructure you have on hand.

If you have a hardware router on your network, which it sounds like you do, why on earth would you bother adding another Win2K box set up as another router?

Nearly all routers (with the exception of firewalls) will allow you to configure multiple IP subnets on a single interface. Simply add the corresponding 10.x network to each interface where the existing 130.x interface exists.

Remember that unless you are NAT'ing that all your 10.x traffic will die a quick death when sent to the real world.

Example of interface config from router.

Interface Ethernet 1/1
IP address 130.1.0.1 255.255.0.0

add second IP to the interface, to look as follows.

Interface Ethernet 1/1
IP Address 130.1.0.1 255.255.0.0
IP Address 10.1.0.1 255.255.0.0

All you would do then is reconfigure the client from A to B.

A) IP Address 130.1.0.25/16 GW 130.1.0.1

B) IP Address 10.1.0.25/16 GW 10.1.0.1

Not sure if this helps or not.

by wayne r.

Our Cisco Router offers internet connection only and is directly connected to our old Firewall-1 box (NT4 SP6a).

The Firewall-1 box takes care of NAT and existing routing, it is the existing default gateway for all machines. I had already assigned the 'internal / inbound' NIC a secondary IP in the 10 range and changed the default gateway on my test station to the new address without success (briefly mentioned in original question).

Unfortunately you haven't mentioned anything I hadn't already tried.

Thanks anyway.

by cactus pete

What errors are you getting from the test box when you try to browse?

Can you browse to the share by using the IP address instead of the servername?

Does your router know that it can reach the 10. network through the Win2k box?

by vanja.janezic

Hi,

1.It is very simple. Try first to connect to shared resource from 10.X.x.x station to 130.x.x.x server or station by simply typing the 130.x.x.x address in the run command in start menu. Do it like this \\130.x.x.x". You should get the list of shared resources on that address.
If this does not work, you have a routing problem. Keep in mind taht win2000 and NT servers do boradcast their addresses and routes, so your router/server is actually listening to this broadcasts and bulids it's own routing table based on this information.
Having 10.x.x.x and 130.x.x.x addresses on one branch and 10.x.x.x addresses on other network branch wont do the job properly. So be shure not to mix the addressing schema.

The bproblem actally is not a problem. As You can't browse to all networks and resources on the Internet, the same is in your network. When you route IP, you route unicast packets and surpress broadcasting. For WIN station to access a network resource by name, you must have some kind of name resolution service. In WIN200 environment, this would be DNS, but when using win98 or older you need WINS (and NetBios over TCP/IP enabled on stations). But you can still reach the resource by addressing it strictly on it's IP address.WINS uses broadcasting to discover and resolve names. In your case the router is stopping broadcasts to span from one network branch to another. YOu can solve this by simply setting the same 2K machine to act as WINS and DHCP server for both networks.

by wayne r.

I know I have a routing problem - it would work if I didn't.

I had previously tried installing WINS on the server that is acting as the router between the two subnets. This did not resolve the problem. I have not tried installing DHCP on this machine though, I can't think why it would make any difference?

by wayne r.

Okay, problem solved.

WINS does not like being installed on a server with a multi-homed NIC. Removed the old 130. address and told both subnets to use the 10. address for WINS and everything works. The routing was working all along.

by wayne r.

FAO: Tech010

Although you didn't provide me with the answer, you were right about it being name resolution and I eventually figured it out by assuming just that.

If you supply another answer to the question I will accept it and award you the points.

This discussion is closed to new replies.