Login|Contact Us
Question and Answer

Networking

Ask a Networking Question, Get an Answer ASAP!

  • Ask A Question
  • Browse Answers
  • Meet The Experts
  • How JustAnswer Works

How do I connect 2 LANs together to form a WAN

 

Customer Question

Picture

How do I connect 2 LANs together to form a WAN? Do I use a router or a switch to connect 2 routers/networks together?

Submitted: 1771 days and 22 hours ago.
Category: Networking
Value: $15
Status: CLOSED
Picture
Expert:  Flagbridge-NW replied1771 days and 22 hours ago.

To connect two LAN's together you need to use a device that is capable of Layer 3 communication.

Most often this is a router, however there are many Layer 3 switches available that can do the same task.

If you give me more information about your actual individual needs i can expand my answer if required.

Regards

Picture
Customer replied1771 days and 22 hours ago.

I have networks, each with its own NAT router. I also have a layer 3/smart switch. Do I just connect the 2 routers to the layer 3 switch so hosts on both networks can communicate with each other?

Picture
Expert:  Flagbridge-NW replied1771 days and 22 hours ago.

Do you want both talking to the internet as well?

Picture
Customer replied1771 days and 22 hours ago.

Reply to Flagbridge-NW's Post: I have a proxy server/ISA server 2004. I want both to get to the Internet through that proxy server.

Accepted Answer

Picture
Expert:  Flagbridge-NW replied1771 days and 22 hours ago.

Ok so here is what you can do (I dont have your network diagram so please bare with me).


Network 1 (N1). We will say is network 10.0.0.0 255.255.255.0

Network 2 (N2). We will say is network 192.168.0.0 255.255.255.0

ISA Machine. (ISA). We will say it is on its own network of 172.16.0.0 255.255.255.0


Take your lawyer 3 switch.

On interface 1, give it the ip address 10.0.0.254 (your gateway address or default route address for that subnet). Plug N1 into Interface 1.

On interface 2, give it the ip address 192.168.0.254 (your gateway address or default router address for that subnet). Plug N2 into Interface 2.

On the last interface on the switch give it an IP address 172.16.0.254 (your gateway address or default router address for that subnet) Plug ISA into that interface. IP the server is 172.16.0.1

------------

Routes,

N1 all machines on N1 have a default route of 10.0.0.254

N2 all machines on N2 have a default route of 192.168.0.254

ISA, Now we need to add a couple of routes to this machine. You need to add

10.0.0.0
192.168.0.0
172.16.0.0

All to point to 172.16.0.254.

You will also need a default route pointing to the external interface (if directly connected to the net or to a router).

The ISA machine can nat for all the 10, and 192.168 address if you want. OR you can put routes on the router so you are only NATing once.

==============


The switch will need a default route pointing to the ISA IP (172.16.0.1)


Expert TypeConsultant
Category: Networking
Pos. Feedback: 100.0 %
Accepts: 107
Answered: 8/13/2008

Experience: Paid for university with 10+ years as a Network Engineer.

Ask this Expert a Question >
Picture
Customer replied1771 days and 22 hours ago.

Reply to Flagbridge-NW's Post: A clarification is needed. When you say, "On interface 1, give it the ip address 10.0.0.254...", do you mean assign the ip address 10.0.0.254 to router 1? Or do you mean assign that IP address to the port of the switch? If you mean assign it to the port of the switch, I'm not sure if that could be done. My layer 3 switch is a netgear switch and I haven't seen a feature in the switch setup pages that will allow me to assign an IP address to a port.

Picture
Expert:  Flagbridge-NW replied1771 days and 22 hours ago.

Port 1 of your layer 3 switch.

You said you had a layer 3 switch, so we are using the switch as the internal routing device.

You may be able to add subnets to the switch, or routes to the switch.

regardless, if it will act as a layer 3 device, it needs to obtain an IP address on each network it will be routing.

Picture
Customer replied1771 days and 22 hours ago.

Reply to Flagbridge-NW's Post: I"m not sure how that can be done on the switch. What about replacing the switch with a router. Can I used any router to connect the 2 routers/networks together? Or does it has to be a special type of router? And how do I connect the 2 routers/networks to the main router? Do I need to setup any routes/configurations?

Picture
Expert:  Flagbridge-NW replied1771 days and 21 hours ago.

Yes you need to do some significant configuration,

In addition you need a router with three PROGRAMABLE ethernet interfaces

Picture
Customer replied1771 days and 21 hours ago.

Reply to Flagbridge-NW's Post: Another Expert told me that I could use any router, but he hasn't gotten back to me on how exactly to connect the 2 networks to the primary router and its configurations. Please explain "significant configuration". Thanks.

Picture
Expert:  Flagbridge-NW replied1771 days and 20 hours ago.

You can not use any router, as then you have no interface to get to the internet.

Youa re trying to get three networks connected together.


You need to configure the router to tell it what networks are on what sides of the interfeace and how to allow certain traffic to go between.

Anyone who says you can use any router is incorrect.

Picture
Expert:  Flagbridge-NW replied1771 days and 20 hours ago.

I see that you have now included information in your second question not in your question here.

Would you prefer I opt out?

Picture
Customer replied1771 days and 20 hours ago.

Reply to Flagbridge-NW's Post: Here is what I got from another Expert and a lot of the researches that I have done were saying that any router could be used to connect 2 or more networks together.

From Expert: "Hello. Yes, you can use any router to accomplish this - that is what a router is for; to connect two networks. You will just need to provide the "WAN" side of the router with an IP address on one network and have all nodes of the second network come into the router.

If the two networks are in the same location, you might consider simply modifying the subnet instead - for example, use 192.168.1.x for one network and 192.168.2.x for the other. Then you wouldn't necessarily need a router at all."


My Reply: "Ok, here is my situation. I have 2 subnets/networks, 192.168.100.1 and 192.168.200.1. Each network has its own router. So let's called the router with IP address of 192.168.100.1 R1 and 192.168.200.1 R2. What I did previously was I connected the WAN port of R2 to one of the switch ports of R1. Hosts from R2 were able to ping R1 but not hosts on R1. Also, hosts from R1 cannot ping R2 or hosts on R2. So I was thinking that it might need a third router to connect those 2 routers/networks together so that hosts on R1 can communicate with hosts on R2 and vice versa.

Let's called the third router, the primary router that will connect R1 and R2 together, as R3. What I did was I connected the WAN port of R1 and R2 to the switch ports of R3. Hosts from both R1 and R2 were able to ping R3 but R1 still cannot communicate with R2 and vice versa. What am I missing?"

So I don't understand the fact that it can only be done using a router with three PROGRAMABLE ethernet interfaces. In fact, I searched online and found very few to almost no information about router with three programable ethernet interfaces. If 2 or more networks can be connected via any router, how and what kind of configurations needed to be done?

Picture
Expert:  Flagbridge-NW replied1771 days and 20 hours ago.

I first started out by saying "Ok so here is what you can do (I dont have your network diagram so please bare with me)."

You didnot explain any of your previous setup to me.

I see why things are not working, and certainly would not engineer it like that.

R1 has no idea how to get to R2 because no static routes exists for it telling it

What type of routers are these

Picture
Customer replied1771 days and 20 hours ago.

Reply to Flagbridge-NW's Post:

First of all, thanks for helping out. Please do not assume that I will not accept answer because I will accept answer(s) by the end of the day. I usually get all of my answers and then accept one or more once the problem is solved.

To your question, these are netgear routers with NAT. Let me know if you need any additional info. Thanks.

Picture
Expert:  Flagbridge-NW replied1771 days and 20 hours ago.

Do you have a network diagram?

Do you have the model number of the L3 switch and the netgrear routers?

Picture
Customer replied1771 days and 19 hours ago.

Reply to Flagbridge-NW's Post: My equipments are at home and I'm still at work. This is my senior project for my BS in IT. As of right now, I have 3 netgear routers with NAT and a layer 3 netgear switch. I want to simulate 2 networks connecting together to form a WAN and both networks are able to communicate with each other using the equipments I have. Let me know if you know of any better way doing it (as long as there are 2 networks of different subnet connected together and can communicate with each other).

Picture
Expert:  Flagbridge-NW replied1771 days and 19 hours ago.

Ok there are a few things you could do PROVIDED that the routers can support it.

In your first scenario you have two issues.

1. If you are natting and the nats are not static, then traffic can only originate from INSDE.

2. If you are sending traffic out an interface you need to know how it will get back. if your router does not know where to send the traffic then it will drop it.

This is why you need static routes, which I explained in detail above.

3. Based on what you have described (sending all traffic through your ISA Proxy, well that is acting as a firewall so BOTH networks need to be on the INSIDE of it.

4. You want to avoid NAT where possible. Use it only when necessary and when you know why you need it.

The feature description on your netgear router may be TADITIONAL ROUTING, which will disable NAT, but force you to enter your static routers, networks etc.

For example you could create a different VLAN for each subnet, and then create a VLAN trunk to your router, which would then route the traffic back and fourth.

Picture
Customer replied1771 days and 19 hours ago.

Reply to Flagbridge-NW's Post:

How do I disable NAT on a router? When I look through the netgear router's setup page, there are two router functions, "Run router as gateway" and "Run router as router". What is the difference between the two? And by choosing "Run router as router", will that disable NAT?

Will it work if I:
1) disable NAT on all three routers, R1, R2, and R3
2 connect WAN port of R1 to R3 switch port
3) connect WAN port of R2 to R3 switch port
4) connect ISA server to R3 switch port

I will have all of the external traffic to the Internet route to the proxy server. Will the proxy server do NAT on incoming traffic? Will this work?

Picture
Expert:  Flagbridge-NW replied1771 days and 19 hours ago.

Yes Router as a Router should disable the NAT.

Routes will not know what to do unless you program and tell it. If you disable NAT you need to set up routes.


You are using equipment that is not designed for this type of configuration. You really shouldbe using an 800 series Cisco router for this.

You always start something like this with a diagram.

So before we continue, as I have spent nearly 45 minutes on your problem today, we need to standardise the approach.

Draw a diagram, including

ALL devices and model
ALL interfaces
ALL IP Address and Subnet masks
ALL Machines, and their features as required
ALL traffic lines, and traffic paths.
CLOUDs for the various networks.

When you have that done, I can review it for you.

 
Tweet

9 Network Technicians are Online Right Now

Ask Your Question Now
Networking Questions Date Submitted
My computer to have one static public IP address. I need assistance 5/29/2013
Hello, I have an Elmo PTC-201C IP camera that I want to 5/22/2013
Hello, I have a fairly simple project of creating a 5/14/2013
Question regarding LinkedIn. I hope this category of Networking 4/23/2013
Have forgotten my password 4/15/2013
why won't my innotab 2s connect to my FiOS router? 4/9/2013
My network stop working today. or shall I say my router? I 4/3/2013
Some one send a bunch of emails and made it sound like I sent 3/27/2013
I have an iPad that has worked perfectly for the last 3 months 3/21/2013
Your neighbor is starting a small billing business and has 3/10/2013
RSS
Next 10 >
Ask A Network Technician
Type Your Networking Question Here...
characters left:

Top Networking Experts

See More Network Technicians

In The News

Nbc
Washington Post
New York Times
Cnn
Learn More

How It Works

  • Ask an Expert
  • Get a Professional Answer
  • Ask Followup Questions
  • 100% Satisfaction Guarantee
Learn More

Ask a Network Technician

Get a Professional Answer. 100% Satisfaction Guaranteed.
131 Network Technicians are Online Now
Type Your Networking Question Here...
characters left:
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.
Truste
Contact Us | Terms of Service | Privacy & Security | About Us | Our Network
© 2003-2013 JustAnswer LLC
  • Pearl.com
  • JustAnswer UK
  • JustAnswer Germany
  • JustAnswer Spanish
  • JustAnswer Japan