I hooked up a cisco 2514 router in my home behind a comecast cable connection, Ive got that connecting via int ethernet0 using dhcp, then use int Ethernet1 to plug into a 3com hub. I can ping all devices in my home network, and if i add a device it is assigning an address correctly the problem is I cant get out to the internet. here is my code Using 1173 out of 32762 bytes ! version 12.1 service config service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname players_den ! enable secret 5 $1$Kdcm$pvnM51jIo9NQupKHEYI9g. enable password ! ! ! ! ! ip subnet-zero ip dhcp excluded-address 10.10.10.1 ! ip dhcp pool CLIENT network 10.10.10.0 255.255.255.0 dns-server 63.240.76.4 204.127.198.4 default-router 10.10.10.1 ! ! ! ! interface Ethernet0 ip address dhcp ip nat outside no ip mroute-cache no cdp enable no mop enabled ! interface Ethernet1 ip address 10.10.10.1 255.255.255.0 ip nat inside no ip mroute-cache no cdp enable ! interface Serial0 no ip address no ip mroute-cache shutdown ! interface Serial1 no ip address no ip mroute-cache shutdown no cdp enable ! ip nat inside source list 102 interface Ethernet0 overload ip classless ip route 0.0.0.0 0.0.0.0 12.248.176.1 no ip http server ! access-list 102 permit ip 10.10.10.0 0.0.0.255 any snmp-server engineID local 00000009020000E0B06A67B2 snmp-server community p RO snmp-server packetsize 2048 ! line con 0 exec-timeout 0 0 transport input none line aux 0 line vty 0 4

On the 2514 run the commands show int eth0 and look to see what ip address has been assigned to the router - you can run an extended ping and use thhe source address of this to ping the default gw 12.248.176.1. I assume that this is the ip address of your comecast cable modem - if you can ping this then I assume that the problem is down to the comecast not having a route to the 10.10.10.0 network via the cisco dhcp assigned address Also not clear as to why you are natting on the cisco as i would have expected the cable modem to also be using nat.