Cisco 2651xm/cable modem problem

I have cox high speed internet and want to start using a Cisco 2651xm router instead of my small appliance router. Here is my basic config:
cable modem -f0/1 port of 2651xm - f0/0 port into small netgear swtich - pc into netgear switch. (the 2651xm has two fastethernet ports)

I have set the f0/1 port to dhcp. It grabs an IP address from ISP from cable modem. I set the f0/0 port to static IP of 192.168.1.254. Pc is set to IP of 192.168.1.2.

I set up RIP routing in the router for network 70.0.0.0 and network 192.168.1.0. (The IP I get from my ISP is in the 70.0.0.0 range.

I can ping both interfaces of the router from my pc, but I cannot ping any address beyond the f0/1 port (any internet addresses). While I am consoled into my router I am able to ping any internet address, so the router is able to communicate w/ the outside world, it is just not passing any requests from my pc to the outside world.


I do not have any acl's setup. I have talked to a friend of mine that works w/ cisco routers alot and he said that he had tried the exact same setup and ran into the same problem. He mentioned that it might be an encapsulation problem. any ideas?

Did you use the correct sub-net masks when setting the IP's for the ports?

Remember RIP [v.1] is a classfull routing protocol and will only use default masks.

Sounds like you are passing traffic to the router with IP addys that are not in its routing table and therfore the router will drop it by default.

What are the exact commands you have used from start to finish?

Can you configure your switch or is it not an intelligent one?

here is my config in the router. I did know that RIP was classfull, so when I put in the commands as follows:
router rip
network 70.0.0.0
network 192.168.1.0
It would have defaulted 70.0.0.0 to a subnet of 255.0.0.0 because it is class A
It would have defaulted 192.168.1.0 to a subnet of 255.255.255.0 because it is class C
So do you think it is unable to pass class C to class A? If so, would the fix be to put my internal network to a class A subnet such as 10.0.0.0?
Here is the config:

version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname BCSRTR03
!
boot-start-marker
boot system flash:c2600-a3js-mz.123-11.T.bin
boot-end-marker
!
!
no network-clock-participate slot 1
no network-clock-participate wic 0
no aaa new-model
ip subnet-zero
!
!
ip cef
!
!
interface FastEthernet0/0
ip address 192.168.1.254 255.255.255.0
duplex auto
speed auto
!
interface Serial0/0
no ip address
shutdown
!
interface FastEthernet0/1
ip address dhcp
duplex auto
speed auto
!
!
router rip
network 70.0.0.0
network 192.168.1.0
!
ip classless
!
ip http server
!
!
!
!
!
control-plane
!
!
gateway
timer receive-rtp 1200
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
end

Can you post your routing table?

Have you tried adding a default route for your gateway?

Code:

---

ip route 0.0.0.0 0.0.0.0 f0/1

---

this basically tells it that if it does not have an entry for a network in its routing table, forward it out of f0/1.

The problem you could be having is that when you want to browse the net and open up a web page with an ip of say 66.21.21.45, when your router gets this packet it doesnt know what to do with it as it has no idea where the ip address 66.21.21.45 is, so it will just drop the packet.

Ok, I have changed some of the #'s for my peace of mind, but it is close enough that I think you will get the idea:

Gateway of last resort is 70.11.11.1 to network 0.0.0.0

70.0.0.0/24 is subnetted, 1 subnets
C 70.11.11.0 is directly connected, FastEthernet0/1
172.11.0.0/32 is subnetted, 1 subnets
S 172.11.0.11 [254/0] via 70.11.11.1, FastEthernet0/1
C 192.168.1.0/24 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 [254/0] via 70.11.11.1

By the way the entries for 172.11.0.11 and that subnet is for the dhcp server on my ISP's side.

Yes I did put that exact command in (ip route 0.0.0.0 0.0.0.0 f0/1) as well as a few others such as:
ip route 0.0.0.0 0.0.0.0 dhcp
which tells it to route all traffic to the default gateway provided to it by the DHCP server. (the closest gateway beyond my router)

You have two static routes in there which have an AD of 1, RIP had an AD of 120. So aslong as you have those static routes in the RT, RIP is pretty much null and void.

You dont really need rip on a network such as this.

so do you have any ideas on how I can get around that? Can I use a different routing protocol such as eigrp to get around it?

also I am new to configing Cisco routers, what is AD of 1 and AD of 120?

are you sure that 172.11.11.0/32 is correct? there cant be a /32 the best you can have is a /30.

AD - Administrative Distance. It is what cisco routers use to chose which route to take, the lower the AD the better.

A directly connecteed route has an AD of 0 and is therfore the best route, a static route has an AD of 1 and is the next best route, RIP has an EIGRP (intenal) has an AD of 90, IGRP 100, OSPF 110, RIP 120, the worst you can have is 255 which is an unkown route and will never be used!

So if you want RIP to work you have to remove the static routes (hence RIP will have the lowest AD after directly connected routes) or put a static route with a higher AD than RIP.

well I did change a few of the #'s and that is one that I changed, so it is not correct, but I'm sure w/ the correct # in there it would be.

Can you post your exact route table? Its not really very helpful if you change it!!

Of course change a digit or two or your external IP but if you can help it dont change anything else. you can PM it to me if you dont want to post it.

It could be one of two things, when your router gets a packet for an internet address (ie one that is not in its routing table) it does not know what to do with it so just drops the packet. Or yours and your ISP encapsulation is different (phone your ISP up for this).

Can you configure your switch or is it not that type of switch?

No I cannot configure the switch I am currently on. here is the exact routing table again:

Gateway of last resort is 70.186.123.1 to network 0.0.0.0

70.0.0.0/24 is subnetted, 1 subnets
C 70.186.123.0 is directly connected, FastEthernet0/1
172.19.0.0/32 is subnetted, 1 subnets
S 172.19.25.22 [254/0] via 70.186.123.1, FastEthernet0/1
C 192.168.1.0/24 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 [254/0] via 70.186.123.1

My friend also thought it might be the encapsulation, but I am not sure how to check that nor how to fix it, if that is it. If you can ping outside addresses while consoled into the router, but not from a pc on the inside of the router, would that still point to an encapsulation problem?

Why use RIP? There's only one router and both networks are directly connected...

Don't you need NAT to translate your RFC-1918 192.168.1.x addresses to your Internet address(es) 70.0.0.x?

Can you ping the default gateway from the cisco?

SirDice: I believe that he does need nat.

At least, that's how I have mine configured on my 831...

On the external interface, use "ip nat outside"
On the internal interface, use "ip nat inside"

Then use

ip route 0.0.0.0 0.0.0.0 externalinterface permanent

obviously, replace whatever your external interface is with the one in the above command.

My config is seriously bloated because I have QoS and VPN setup along with some pretty lengthy ACLs for various services, interfaces... but I can remove all that "junk" and post my config. Though, my config will be slightly different because I'm using aDSL and not cable.

I do have another Cisco 806 that I can configure on one of my cable connections and then post the config...

I will try the NAT commands that you posted, but phishphreek80, if you could hook that cisco 806 up to one of your cable connections and then post the config, that would be VERY helpful. I hope and am sure you will be more successfull than I have been at getting it to work. Thanks for the help. By the way, does that 806 have dual ethernet ports?

Try out those commands... it *should* work for you. I won't have time to configure up the 806 until late this weekend. I've already got a booked schedule and I have no time for "fun". So, if you don't have yours working by then, I'll do it.

Quote:

---

does that 806 have dual ethernet ports?

---

Yes, it is a broadband router. It has a eth0 and eth1 for wan and lan. However, my eth0 gets reasigned to Dialer0 (which is a virtual interface) because I'm on DSL. If I were only using cable, then there would be no need for the Dialer0 virtual interface.

I originally started with an 806 but quickly outgrew it. I've upgraded to an 831, but again, I'm outgrowing it. I'd like to get an 870 series... but I don't want to shell out the $ again. I've spent more $ on routers than any other hardware.

Check out the 800 series for more info.
http://www.cisco.com/en/US/products/hw/routers/ps380/

I tried those commands, and they did not work for me. I was under the impression that you only needed those nat commands if you were going to do port forwarding? Not sure. That is cool about not being about to set up the cisco 806 to cable until late weekend. Do you think you could go ahead and shoot me your config from the 831 on DSL to tide me over? Thanks.

Hey I got it figured out. after I put in the NAT statements, I had to create an ACL and apply it to the external interface, (access-list 102 permit ip 192.168.1.0 0.0.0.255 any) now it is passing traffic. Thanks for all of your all's help!!