Connecting two sites (different IP ranges, Subnets) together via Ethernet

[bharlieatwork]

Hi everyone, I was wondering if you could help me.  I work for a split site school in which we're trying to connect together via a new dedicated Ethernet connection provided by our telephone company.

Background:

The two sites are about a mile away from each other, and both have their own network.  Each site uses Cisco switches and has servers dishing our two different IP/Subnet/DNS ranges for the particular site.  Both sites also have their own Smoothwall Internet Firewall, which allows the site to connect to the internet.  This firewall also has an IPSEC configuration, which allows the two sites to communicate.

To improve speed, we've now installed a new 100mb ethernet connection between the two locations (provided by BT) - which is now up and running, ready to be used. (We connected a PC on each end and pinged each other).

Now comes the tricky bit!  

I want to connect the two sites together, but aren't sure how to configure the Cisco 3750 switches.  

Currently the main switch on each site has a "Default Route Forwarding IP" set to its site's internet firewall.  Each site also has a "Static IP Routing Protocol" pointing to the internet firewall as well.

My question is, can we simply add another Static Destination/Network IP entry? Or do we need a router on each site so the network on each site knows to send network traffic across the link, and internet traffic to the firewall box?

Thanks​ for any help you can give.​

[Seb Rupik · Accepted solution]

Hi there,

The reduce the amount of configuration required with routing I would connect your new cross site link to a new interface on the smoothwall firewalls. This way each site still forwards all outbound traffic to the firewall, and the routing table on the firewall would have an entry for the other site (statically or dynamically configured) which it would route traffic down.

You also have the benefit of securing the cross-site link by using the firewall.

cheers,

Seb.

[bharlieatwork]

Thank you for your reply, luckily we have support from Smoothwall for configuring our boxes - I had the same idea originally, but i didn't want to put too much strain on these boxes, but thinking about it, they should be able to handle it.

Thankyou for your advice with this.

[Mark Malone]

Hi
static routes should work fine , shouldn't be a requirement for anymore routers, 3750 are l3 capable and even with base license static routes can be configured think up to 16 from memory