How to simulate the internet in my lab?

motherwolf

Hey all,
I have a nice lab set up at home and I'm wondering how I can simulate the internet on my internet facing lab router. The LAN side is set up with a 192 address and my WAN side serial interface is a 68.x.x.x address. How do I simulate the ISP address I'm going to be accessing the (fake) internet through?

I also have a question in regards to loopback interfaces. I want to simulate a PC connected to another one of me lab routers (since I don't have an extra PC laying around). I tried setting up the fa0/0 int with 192.168.3.1 and then the loopback int with 3.2. But it wouldn't allow it saying the two addresses were overlapping. Do I just set the loopback int address and forget about the fa0/0 int? Any help is much appreciated, thanks.

jbrad95706

For the loopback question:

To my understanding you can't have two interfaces pointing to the same network.

So, with Fa0/0 being on the 192.168.3.0 network, the loopback can't have an address on the 192.168.3.0 network. You can however setup your loopback with an ip from another network. (ex. 192.168.4.1)


Also, I don't know that there is a way to really simulate the internet; however, I could be wrong.

What are you trying to do that for? There are other ways to send traffic through your network - tcpreplay, etc.. this can get a little wild and fun! You could also run your home network traffic through your lab (the family loves this option... ), or setup a few loopbacks and just throw some pings around.

networker050184

I'm not sure what you mean by simulating the internet. Do you just want to simulate your WAN connection to the provider? If so just practice setting up PPP and frame relay links.

captobvious

motherwolf wrote: »

Hey all,
I have a nice lab set up at home and I'm wondering how I can simulate the internet on my internet facing lab router. The LAN side is set up with a 192 address and my WAN side serial interface is a 68.x.x.x address. How do I simulate the ISP address I'm going to be accessing the (fake) internet through?

I also have a question in regards to loopback interfaces. I want to simulate a PC connected to another one of me lab routers (since I don't have an extra PC laying around). I tried setting up the fa0/0 int with 192.168.3.1 and then the loopback int with 3.2. But it wouldn't allow it saying the two addresses were overlapping. Do I just set the loopback int address and forget about the fa0/0 int? Any help is much appreciated, thanks.

You would make the simulated "pc" a secondary ip address on the interface:

interface fa0/0 ip address 192.168.3.1
interface fa0/0 ip address 192.168.3.2 secondary

Then you should be able to ping both addresses.

wbosher

networker050184 wrote: »

I'm not sure what you mean by simulating the internet. Do you just want to simulate your WAN connection to the provider? If so just practice setting up PPP and frame relay links.

Just a wild guess, but I think motherwolf may be trying to set up NAT. I have the same issue which is why in another post I inquired about setting up a Cisco 2600 series router and a DSL modem to do this.

Link to that thread - http://www.techexams.net/forums/ccna-ccent/45267-dsl-router-config.html

hypnotoad

You could send yourself spam, poorly-worded 140 character messages of randomness, and **** popups. This would simulate most user's internet experience.

motherwolf

Thanks for the replies. Yeah, like Networker said, I just want to simulate the connection to my provider.

dynamik

hypnotoad wrote: »

You could send yourself spam, poorly-worded 140 character messages of randomness, and **** popups. This would simulate most user's internet experience.

Oh, you're on Twitter too?

mikej412

networker050184 wrote: »

Do you just want to simulate your WAN connection to the provider?

Yeah, you don't really simulate the Internet -- it's more like you pretend it's there.

Toss an extra "ISP Router" into your lab and create /32 loopback interfaces on that to pretend to be other hosts or resources on the internet. Anything that isn't in your local lab network should get sent to that "ISP Router" -- and that link to the ISP Router is where you'll be practicing your default routes, NAT and Security.

seraphus

motherwolf wrote: »

I also have a question in regards to loopback interfaces. I want to simulate a PC connected to another one of me lab routers (since I don't have an extra PC laying around).

You can use a loopback address.
When you ping a given address, source the loopback to simulate
pinging from the pc.

ex
ping 192.x.x.x source 1.1.1.1

billscott92787

I have practiced doing this with either a loopback or adding another router, connecting it by a serial interface, and then configuring it with another network address. I just configured a default route on the gateway router, and redistributed it when using EIGRP or OSPF.