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lan/wan subnet with multiple domains

By breers ·
Good Morning ,
Question ....I have an internal lan on a 255.255.255.0 subnet, and a 172.16.2.X
ip scheme....We are installing our first wan to an outside source through a T-1
and router...There will be multiple offices opening soon and I want the scheme to
portray their office number such as ip 172.16.7.X for office 7 etc...The only way
I could get pings from the wan to our lan is changing the subnet to 255.255.0.0
I have tried many types of subnets but on the 255.255.0.0 subnet, all machines
are time out intervals. We have tried different hubs, nics, etc, but we get good
pings and the next attempt it times out.

Thanks for any suggestions in advance...
Brian

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lan/wan subnet with multiple domains

by Howley In reply to lan/wan subnet with multi ...

This sounds like a gateway issue there should be no reason why you cannot use the mask 255.255.255.0. When I have had problems with this in the past it was an issue with the way the router was configured or the gateway that was assigned on the computer. If the ip for the lan side is not within the subnet or the or the gateway is not configured properly on the PC it could cause this because it is not trying to talk to the router or it is looking for a gateway not on the subnet. When you expand the subnet, it seems to find the gateway it is looking for fine. I would check the gateway and router settings if you haven't already to make sure they are all in agreement with the ip scheme you describe.

Hope this helps!

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lan/wan subnet with multiple domains

by breers In reply to lan/wan subnet with multi ...

The question was auto-closed by TechRepublic

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lan/wan subnet with multiple domains

by bowieb In reply to lan/wan subnet with multi ...

Your offices should continue to use the 255.255.255.0 netmask. This will keep broadcast and local traffic from intruding on your LAN connections. The router connected to your T1 will have routes to your other offices.

The PCs in your office should be setup like this:
(Assuming router is 172.16.2.1)

IP Address: 172.16.2.X
Netmask: 255.255.255.0
Default Gateway: 172.16.2.1

Your router will have routes to the other offices (172.16.7.0, etc) which point to their routers.
For example:
ip route 0.0.0.0 0.0.0.0 172.16.7.1

The details of this will depend on exactly how your WAN is configured. If you can give details on how your routers and T1s are configured (where the connections are and what IP addresses you want to use forthe offices), I can give you a bit more detail on how the setup will work.

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lan/wan subnet with multiple domains

by breers In reply to lan/wan subnet with multi ...

The question was auto-closed by TechRepublic

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lan/wan subnet with multiple domains

by eBob In reply to lan/wan subnet with multi ...

You did not say what your WAN link is. But the LAN addresses you are using (172.16.a.b/12) are covered by RFC1918 as being nonroutable across the public network(s).

Perhaps your provider is blocking your chosen network addresses? This is guaranteed if you're trying to route across the Internet. To get around this, you can get some "public" addresses from your provider for both your WAN links, and to do address translation at your routers. Use Port Address Translation (PAT) to extend the useof this address space, when you don't need a one-to-one translation (like with most workstations). Only use Network Address Translation (NAT) when you need to force a one-to-one translation (like to a server or other device.

Hope that helps.

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lan/wan subnet with multiple domains

by eBob In reply to lan/wan subnet with multi ...

...or use "ip unnumbered" on private WAN links.

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lan/wan subnet with multiple domains

by breers In reply to lan/wan subnet with multi ...

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lan/wan subnet with multiple domains

by joshg In reply to lan/wan subnet with multi ...

You will have to have the 172.16.2.X for one net then 172.16.7.x for another, now you also have to have a net for the routers to talk on, lets say 172.16.10.X. All subnets should be 255.255.255.0 with the gateways being the router at each office. At the roters themselves you will have to add the routes, for each router ex: 172.16.10.2:
ip route 172.16.7.0 255.255.255.0 172.16.10.1

this assumes the routers serial interface has the address of 10.2 and the Ethernet address of 2.1. The otherrouter should have Serial IP of 10.7 and Ethernet of 7.1.

As another person mentioned, these are only internal IP's they can be routed over private networks only. If you are creating a WAN over the Internet you will have to get real IP's.

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lan/wan subnet with multiple domains

by breers In reply to lan/wan subnet with multi ...

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lan/wan subnet with multiple domains

by breers In reply to lan/wan subnet with multi ...

This question was auto closed due to inactivity

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