Need Assistance Config'ng Cisco 1721

[chugger93]

I have a used Cisco 1721 I got ahold of and want to set it up for my comcast broadband access. I ordered the WIC-ENET card from ebay and already popped it in there and successfully consoled into the router. I had to reset the register to 0x2102 because it wasn't saving my config on bootup.

Anyways, Im a newb to Cisco and only know basic things. I have my config below. I've tried reading through Cisco documentation but can't find anything hard in terms of setting it up for broadband.

I basically want both interfaces configured, DHCP, and I think so far, Im still missing comcast gateway on my interface and maybe NAT and some ACL's? Any help on this one?


Ok I think I got further now, and even set a password for telnet! It helps to read and read and read the documentation

Below is my config...however I still cannot get internet. My Ethernet0 side is configured with the correct IP and subnet. However dont I need to put in comcast's gateway and DNS servers? How? See anything else from this config that needs addressing? Please let me know, Im new to Cisco and enjoying it...

oh and also, can I setup my router as a basic firewall for now until I get something else? If so how...

User Access Verification

Username: Jon
Password:
Router>en
Password:


Router#show run
Building configuration...

Current configuration : 678 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$Vqra$ZK3bq0OvZ9PXYBcgCS0sI/
!
username Jon password 0 __________
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
no aaa new-model
ip subnet-zero
ip cef
!
!
!
no ftp-server write-enable
!
!
!
!
interface Ethernet0
ip address 68.61.*.* 255.255.254.0
half-duplex
!
interface FastEthernet0
ip address 192.168.1.10 255.255.255.0
ip nat inside
speed auto
!
ip classless
no ip http server
!
!
line con 0
line aux 0
line vty 0 4
login local
!
!
end

[ErikD]

Well a couple of quick things.

1. Do you have a static IP from your ISP? Because that config uses one.
2. You have no route to the internet. You either need to use a routing protocol (BGP, EBPG, etc.) to find them dynamically, or set a default route. As you are using cable and no routing between you and the internet (you advertise your network) is needed you will need to set a manual default route. You can either point to the interface connected to the internet, or use the IP of the next hop (gateway provided by your ISP).

[chugger93]

no static IP from comcast, I'm always sure they assign DHCP addresses. Probably my first mistake. So I'd have to figure out how to DHCP that interface.

I understand having a default route. Not sure what Id put there. Ive seen them in other routers like "ip route 0.0.0.0 0.0.0.255"

[YeOldeStonecat]

You'll want to power off your Surfboard modem or Arris MTA for several minutes...so it forgets the MAC of your old device that was connected to it..learn the Ciscos MAC...and gives it a legit pub IP. Else, the Cisco will probably pickup a 192.168.100.xxx address and get you nowhere fast.

[ErikD]

no static IP from comcast, I'm always sure they assign DHCP addresses. Probably my first mistake. So I'd have to figure out how to DHCP that interface.

I understand having a default route. Not sure what Id put there. Ive seen them in other routers like "ip route 0.0.0.0 0.0.0.255"

Well if you are getting an address via DHCP then it should be automatically updated. Just for reference though you set the default route like this:

ip route 0.0.0.0 0.0.0.0 [next hop IP address or exit interface]

I am not sure of your IOS but the command to set the internet interface to use DHCP should be:

ip address dhcp setroute