Basic P2P Setup Help Needed

lidanny-half · ‎02-09-2005

My company has recently had a private p2p T1 line setup between our facility and a nearby building. The line is data only. It will be used to replicate data to an Iomega NAS device. The replication will be handled by Doubletake. We purchased two Cisco 1841 routers with T1 wic's. Could somebody out there provide me with a checklist of steps to setting this up. I am planning to connect one router to the switch at our facility then plug it into the T1, set the other router up at the remote site by plugging it into the T1 and then can I just use a crossover cable to go from the router to the NAS device? Then can I just assign ip addresses to the routers and be done? We use 10.0.0.xxx at our facility now so would I just assign valid addresses to the router lan interfaces and be okay. I don't mind doing a little reading so a reference to a good howto would be appreciated as would any advice. All we are looking for is a good copy of our data if the place burns down. We do a full backup every night but our data is always changing and we need this in the event of a disaster between backups.

frennzy · ‎02-09-2005

Piece of cake. Just look at the attached two configs (router A and router B), and look at the picture in the word doc attached.

If you need any other help, just let me know. FYI, I pulled these configs from Cisco ConfigMaker2.6, using a 1751 router, since it doesn't have the 1841. Your setup will be very similar. I used 10.1.1.0/30 for the p2p link, 10.1.2.1/24 for site A (NAS?) and 10.1.3.1/24 for site B.

lidanny-half · ‎02-10-2005

Ok thanks. So right now my NAS device gets an ip from DHCP. Should I leave it that way? If so will it get the ip address from the remote DHCP server or should I set the router up to give out addresses? And an even more basic question is: Can I resolve and communicate with 10.1.2.x ip's when I use 10.0.0.x at our main facility? Sorry if that question is too basic for this forum but I don't usually do anything beyond the most basic network setup.

vitancr · ‎03-11-2005

please send me the config if yo do not mind at cvitan@hotmail.com

TY

vnirmal112 · ‎02-09-2005

Hi,

Let me know if ur using the link only for Replication of NAS Device.If its so, u need not require 24 bit subnet.U can as well use 30 bit subnet.

Nirmal.

lidanny-half · ‎02-10-2005

Yes it is just for the NAS device. Right now my NAS device gets an ip from DHCP. Should I leave it that way? If so will it get the ip address from the remote DHCP server or should I set the router up to give out addresses? And an even more basic question is: Can I resolve and communicate with 10.1.2.x ip's when I use 10.0.0.x at our main facility? Sorry if that question is too basic for this forum but I don't usually do anything beyond the most basic network setup.

frennzy · ‎02-10-2005

The answer is yes, it will be able to communicate...depending on one or two things.

First, what is the scope of your 10.0.0.x subnet? (what is the netmask?)

You should understand that, in order for devices to communicate across routers, each interface on each router needs to be connected to different subnets (that is the purpose of a router). There are other, trickier things you can do, but yours is a very simple setup.

Essentially, what you need to do is assign a subnet to the remote site, (yes, it can be a /30), a subnet to the p2p link itself (it can even be a /31, depending on what code your routers are running), and a subnet at your main site.

Since you already have a subnet defined at your main site, you'll want to use a subnet that is different. Is the main site your only currently network site? You don't have a larger company that you haven't mentioned, do you? I ask because you need to make sure, if you aren't responsible for assigning subnets, that you contact someone who is.

That said, in order for the NAS to get an IP address from DHCP, you will need to setup the DHCP relay component on the router at the remote site...the command is:

ip helper-address (ip.of.dhcp.server)

You will need to make sure you create a scope on the DHCP server to accomodate the requests from the new subnet at the new site. (It has to match the subnet you define on the ethernet interface on the new router).

The subnets you use on the new site and the p2p T1 will be dependent on what subnet mask you currently use at your main site, and what, if any, other subnets may need to exist in your routing tables (which is why I asked about other sites in your company)

Also, do you have an internet connection at your existing site? If so, it is probably your default gateway, so you'll want to make sure that it knows about the new route to the remote site, either via static routing or including the route in your dynamic routing protocol, if you use one.

lidanny-half · ‎02-10-2005

Our main site uses 255.255.255.0 and our default gateway is 10.0.0.1 which is a Cisco Pix 560E that is connected to an MCI managed Cisco 2600 series router. So I would set this static route up in the firewall?

frennzy · ‎02-10-2005

Yes, you would.

route inside 10.1.3.0 255.255.255.0 10.0.0.253*

(*or whatever the inside interface of the new 1841 router at your main site is)

You could also add a route to the point to point link as well, so you could connect to either of the serial interfaces directly.

dbellaze · ‎02-10-2005

Actually adding a route to your PIX firewall will not route you to either of your new routers because you cannot route off interfaces (redirect traffic on the same interface) on PIX firewalls yet.

If you want to route your network to the new routers and your PIX you will have to first route to a router.

For example in this set up you could actually set your default gateway to your new 1841 local router and set the 1841's default route to point to the pix.

ip route 0.0.0.0 0.0.0.0 10.0.0.x

The route to the remote network on the PIX is valid if the traffic is sourced from the PIX, or enters the Outside interface (which requires static translations , ACLs etc).

Daniel

frennzy · ‎02-10-2005

Whoops.

I believe Daniel is correct. His solution is the simplest, as well, unless you have a very limited set of hosts that will need to connect to the remote NAS. If that is the case, you can just use static routes on the server/hosts in question.

On a windows box, this would be done at the command prompt:

route add -p 10.1.3.1 netmask 255.255.255.0 10.0.0.254

(the -p option makes the route persistent across reboots)