Cisco 871 wireless router - part 1

Once again I have proved to myself (the hard way of course) that you can't navigate the Internet using a private IP address. I'm trying to set up a cisco 871 wireless router.

I'm replacing a linksys wrt54g that may or may not work (what I know for sure is that I cannot make it work). I hooked up the 871w but could not access the Internet with my laptop thru the 871. Mind you, this is with the laptop connected to the 871 with a standard ethernet cable! I haven't even tried to use it wirelessly yet. After lots of cussing and fruitless searching on the Internet, it came to me that the source address of the packets from my laptop was 10.10.10.4 (Private!!!!!) which is on the little LAN that the 871 automatically created. So any device that I tried to contact out on the Internet could only chuckle at my foolishness as it thru my packets on the floor.

Consumer level routers (such as the wrt54g) may have their troubles, but I'll give them this: They don't make you jump thru hoops to set up NAT just to allow you to browse the Internet; they do NAT for you. The 871 does not. So that was my trouble. I needed NAT working so the device on the far end had an actual working public address to answer back to. The relevant part of my config now looks like this:

interface FastEthernet4
ip address dhcp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto

interface Vlan1
description $ETH-SW-LAUNCH$INTF-INFO-HWIC 4ESW$
ip address 10.10.10.1 255.255.255.248
ip nat inside
ip virtual-reassembly
ip tcp adjust-mss 1452

ip nat inside source list 23 interface FastEthernet4 overload

access-list 23 permit 10.10.10.0 0.0.0.7

The 871 now NATs the laptop's private source address into the 871's public address. The bright side of this story is that I figured the problem out all by myself. Now it's on to trying to get my laptop connected WIRELESSLY to the Internet thru the 871. I'm sure I will eventually get it done, but not without a little more cussing and fussing.