04-17-2009 12:38 AM - edited 03-04-2019 04:24 AM
Hello.
Having recently bought a Cisco 1841 and learning how to set things up by the minute I'm now at the point of understanding how NAT works.
I've set up Interface FastEthernet0/0 on the router with ip 10.10.10.1, sub mask 255.255.255.248. It's also acting as a DHCP server.
My wish is for the clients on the LAN to have access to Internet. Currently sitting in SDM on a PC looking at Configure/NAT/Create NAT Configuration and the "Basic NAT" seems like a good idea but it requires me to have two router interfaces configured. I assume the other interface should be the WAN one on the router? I have a static IP from our ISP along with dns, gateway and such but I can't find where to input this data in SDM.
Any advice is greatly appreciated. Please take note that I am a novice in networking so most of your information will be new (and very helpful) to me.
04-17-2009 05:49 AM
Craig
Sorry but i haven't used SDM but from the command line you would do the following. For this example fa0/1 is your WAN Interface -
int fa0/1
ip address 195.17.10.2 255.255.255.248 <-- this is IP from your ISP
ip nat outside
int fa0/0
ip nat inside
ip route 0.0.0.0 0.0.0.0 195.17.10.1 <-- this default-gateway supplied by ISP
access-list 101 permit ip 10.10.10.0 0.0.0.255 any
ip nat inside source list 101 interface fa0/1 overload
You will need to add the DNS server that the ISP gave you into your DHCP config on the router.
Jon
04-17-2009 06:28 AM
Thanks alot for your reply Jon, I'll be doing this on Monday and see how it turns out.
Quick questions,
1. How do I find out the name of my WAN interface port? It's labeled CTRLR T1/E1 0 on the actual router (1841). I assume you can't use the FE0/1 port as a WAN port.
2. In your example, what exactly is the int fa0/0? My guess would be that it's short for interface fastethernet0/0 (which is my current LAN port)?
Since I'm new with Cisco stuff, SDM helps a bit more initially, not that I mind doing it through the command line but there's so much syntax I yet have to learn.
Thanks again.
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