I have a DSL and a Cable modem (COX Cable) connection to my office. Is
it possible for me to use a router (cisco or otherwise) and use both
connections.

I would then like to have a local network with NAT for an exchange
server going through the cable model network and a web server going
through the dsl network.

Please provide two devices which are commonly used to do this.

How much are you willing to pay? 

You need an IOS cisco router with a WIC-1ADSL and Ethernet ports.  The
cheapest mod router is a Cisco 2600.  The card above is about $500 new
and cheaper on Ebay as expected.  Below you'll find generic configs
for your setup.




http://www.siliconvalleyccie.com/cisco-hn/dsl-router.htm

Any amount is fine. On the page you listed there is a line:

ip address 97.158.253.25 255.255.255.248

I know the DSL & Cable provider will not give me my own subnet to put
on the external ethernet ports. Can you confirm that I can still route
to a public IP on a large subnet?

If you are serious about running a VERY complicated service such as
Exchange Server, it's my recommendation that you sign up for an option
that will provide you with a few IPs (usually 5) so that you can
assign the NT box its own IP address, same with a web server.  It?s up
to you at this point to utilize the IOS to perform NAT.

Now, I highly discourage the following but I?m including it as FYI:

-	Use your cable modem ISP to PAT (Port Address Translation) to the Exchange box
-	User your DSL ISP to PAT to web server



http://www.cisco.com/warp/public/556/nat-faq.html

I have many customers with this sort of configuration - a Cisco 1720
with two WIC-1ENET will do the job. Please don't buy it from Ebay as
most of the stuff out there is counterfeit - http://optimumdata.com is
trustworthy and they have plenty of 1720s - ask for Joe and tell him
Neal sent you.

 The free answer is that you'd have a NAT statement for each public
interface, use object tracking on the Cox side to tell you when to
switch over to the DSL, and you'd policy route the http traffic coming
from the inside to ensure a return to requester via the DSL.

 If you want to talk to someone who has done such things before you'd
better figure an hour or two at not less than $125/hour. Sorry to
burst you bubble but people with Cisco skills like that won't work for
McDonald's type wages :-(

The best solution I've found so far is from Hawkingtech.com. They
(along with a slew of other hardware providers) provide a dual wan
router, native "bonding" and NAT.