How to setup 1720 With Cable Modem?

[PTALLY]

Hello,


I am looking to setup my 1720 router to my cable modem service. Currently I am running IOS 12.2(15)16T and I need to know how to configure my router. I have 1 fast ethernet port and 1 10BaseT ethernet port, and I do not have a static IP do I require one? So I am trying to see if my external 10BaseT ethernet port can receive DHCP from my ISP? Any help on confguring this would be greatly appreciated.

Thanks,

PTALLY

 

[EddieVenus]

There are a few things you need to consider.

First off this does not sound like you have the firewall IOS. What does this mean? It means that you probably do not want this router connected to your internet connection. It means that you would be further ahead with this router behind a different firewall.

Secondly, go into enable mode, then config mode (type config t to access config mode). Then go to the interface you want on the WAN. I will assume it is int ethernet 0. type 'int e0'. this will get you to interface config mode. then just type 'ip address dhcp setroute'. This will configure that interface to use DHCP to get an address, and to set the gateway of last resort.

Above and beyond that, you have to consider how you want to use access lists to restrict traffic. What ranges of IPs you want to have telnet access, since it is enabled on all interfaces and from all IPs by default. Even though you may have set the password, that is far from secure. Trust me on this.

If you are really interested, find someone hwo owns a Cisco support contract, and ask to use their CCO account to log into the cisco web site. All the info you would want to know is there, and it sounds like you could use a good place to start securing and configuring this router.

eddie venus

 

[PTALLY]

Thanks for the inside tip which IOS do you recommend that has the firewall capabilities for my router? I will also look into finding someone who hass access but if I do not then what do you recommend?

Thanks Again,

PTALLY

 

[PTALLY]

Also I just tried to set DHCP on my fasteth 0 and it gave me % Invalid input detected at '^' marker. I inputed

Router(config-if)#ip address dhcp setroute
^
% Invalid input detected at '^' marker.

Is there something else I need to do?


Thanks,

PTALLY

 

[lambent]

ip address dhcp setroute"

I know "setroute" appears in PIX, but I'm not sure if it appears in IOS too.

So maybe just simply use "ip address dhcp". For the default route, you'll have to use "ip route 0.0.0.0 0.0.0.0 ethernet0" (I assume you use ethernet0 as the WAN interface) although it's highly not recommended to use a broadcast media interface as the outgoing interface in a static route due to the arp issues.

 

[PTALLY]

Router(config)#interface faste 0
Router(config-if)#ip address dhcp
^
% Invalid input detected at '^' marker.

I am still getting invalid for dhcp setup.

Ok what do you recomend me doing to have secure setup for a 1720 what config should I use having 1 WIC 1ENET and 1 fast ethernet port? how can I set this all up for my cable access any help would be greatly appreciated.

Thanks.

PTALLY

 

[plshlpme]

on my dialer interface i use
ip address negotiated

give that a try...
im not sure if its different on fast e's

 

[lambent]

You should be using E0 as your WAN. So try the "ip address dhcp" on E0. If you still got invalid input, then type "?" to check the available options after every word.

 

[PTALLY]

Thanks for the help so far on this. What I have now is i finally got my eth0 working and my fasteth 0. I am now trying to use eth 0 as my wan and I have setup my fasteth 0 for internal network serving as a dhcp server. I do not have a static IP on my wan interface as i am only running dhcp through my cable. what I did was to take the dhcp ip address and assigned it to my eth 0 to test out. now i am able to actually reach the internet as I can ping any external IP address from my router. i wasn't able to set DNS on eth o as it gave me errors what do I do to setup DNS?

On my fasteth 0 I made the default-router my external address what else do I need to do? Any help with this would be greatly appreciated.

Thanks,

PTALLY

 

[lambent]

You need to set DHCP and NAT...

!
no ip dhcp conflict logging
ip dhcp excluded-address 192.168.0.1 192.168.0.30
!
ip dhcp pool yourpool1
import all
network 192.168.0.0 255.255.255.0
default-router 192.168.0.1
dns-server 65.14.65.14 65.14.66.14
lease 0 24
!
access-list 10 permit 192.168.0.0 0.0.0.255
!
interface e0
ip address dhcp
ip nat outside
!
interface f0
ip address 192.168.0.1 255.255.255.0
ip nat inside
!
ip nat inside source list 10 interface f0 overload
!

For the DNS servers, I think you'll have to ask your ISP to get the IP addresses. Or you can just plug your PC to the modem and see which DNS servers you got.