So after a little digging on this site I think I fond what I was looking for. I'm actually surprised at the amount of friends/co-workers I have in the IT field who have never configured NAT overload (PAT) on a CISCO ASA before (because they are much smarter than me when It comes to networking I was just a little surprised).
First, I found out that the ISP will completely work with you on how you want the setup to be - meaning, If you want them to provide DHCP for your or not. The reason I mention this is because for a small business, I would prefer to have a windows server manage the DHCP and DNS (with the DNS addresses of course coming from the ISP as well). I know the router could run DHCP and DNS but for a small business I would prefer to have a server manage it.
The static route to be set would have to be for the ISP router THIS is the address that I would use for default gateway on my server as well, so in short I would run the following command on my router to set the default route:
ip route 0.0.0.0 0.0.0.0 2.2.2.1 (with 2.2.2.1 being the ISP router) OR I would simply set the "default gateway" with ISP'S IP.
From there, I could proceed to NAT overload (PAT) by doing the following (note: I retrieved all the following info from this article online: http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/260-cisco-router-nat-overload.html)
Set the fast ethernet 0/0 interface as the inside interface:
R1# configure terminal
R1(config)# interface fastethernet0/0
R1(config-if)# ip nat inside
Next step is to set the serial interface S0/0 as the outside interface:
R1(config-if)# interface serial0/0
R1(config-if)# ip nat outside
R1(config-if)# exit
now need to create an Access Control List (ACL) that will include local (private) hosts or network(s). This ACL will later on be applied to the NAT service command, effectively controlling the hosts that will be able to access the Internet. You can use standard or extended access lists depending on your requirements:
R1(config)# access-list 100 remark == [Control NAT Service]==
R1(config)# access-list 100 permit ip 192.168.0.0 0.0.0.255 any
The above command instructs the router to allow the 192.168.0.0/24 network to reach any destination. Note that Cisco router standard and extended ACLs always use wildcards (0.0.0.255).
extended ACLs always use wildcards (0.0.0.255).
All that's left now is to enablee NAT overload and bind it to the outside interface previously selected:
R1(config)# ip nat inside source list 100 interface serial 0/0 overload
From this point onward, the router will happily create all the necessary translations to allow the 192.168.0.0/24 network access to the Internet. AND THAT'S IT!!
Now, I will have to learn how to use an additional firewall if I don't intend to use an ASA for the setup (All the above is done on a standard router) but that's going to have to be something I need to look into, I also know the commands for setting up PAT on an ASA.
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The following is additional info relating to how to look into the way your PAT setup is working:
Verifying NAT Overload operation
Viewing the NAT translation table can sometimes reveal a lot of important information on your network's activity. Here you'll be able to identify traffic that's not supposed to be routed to the Internet or traffic that seems suspicious.
As packets start traversing the router it will gradually build up its NAT/PAT translation table as shown below:
R1#
show ip nat translations
Pro Inside global Inside local Outside local Outside globaludp 200.2.2.1:53427 192.168.0.6:53427 74.200.84.4:53 74.200.84.4:53
udp 200.2.2.1:53427 192.168.0.6:53427 195.170.0.1:53 195.170.0.1:53
tcp 200.2.2.1:53638 192.168.0.6:53638 64.233.189.99:80 64.233.189.99:80
tcp 200.2.2.1:57585 192.168.0.7:57585 69.65.106.48:110 69.65.106.48:110
tcp 200.2.2.1:57586 192.168.0.7:57586 69.65.106.48:110 69.65.106.48:110
As shown, the first 2 translations directed to 74.200.84.4 & 195.170.0.1 are DNS requests from internal host 192.168.0.6. The third entry seems to be an http request to a web server with IP address 64.233.189.99.
Looking at the fourth and fifth translation entry, you should identify them as pop3 requests to an external server, possibly generated by an email client.
Because these entries are all dynamically created, they are temporary and will be removed from the translation table after some time.
Another point you might want to keep in mind is that when we use programs that create a lot of connections e.g Utorrent, Limewire, etc., you might see sluggish performance from the router as it tries to keep up with all connections. Having thousands of connections running through the router can put some serious stress on the CPU.
In these cases, we might need to clear the IP NAT table completely to free up resources.
This is easily done using the following command:
R1# clear ip nat translation *
Assuming no request has been sent right after the command was entered, the NAT translation table should be empty:
R1# show ip nat translations
Pro Inside global ...........Inside local .....Outside local .......Outside global
Lastly, you can obtain statistics on the overload NAT service. This will show you the amount of current translations tracked by our NAT table, plus a lot more:
R1# show ip nat statistics
Total active translations: 200 (0 static, 200 dynamic; 200 extended)
Outside interfaces:
Serial 0/0
Inside interfaces:
FastEthernet0/0
Hits: 163134904 Misses: 0
CEF Translated packets: 161396861, CEF Punted packets: 3465356
Expired translations: 2453616
Dynamic mappings:
-- Inside Source
[Id: 2] access-list 100 interface serial 0/0 refcount 195
Appl doors: 0
Normal doors: 0
Queued Packets: 0
