internet via router

Hi,

A modem is connected to my router and my pc to the router. The router has DHCP enabled and i have set the PC to obtain an an IP address dynamically. I am however still seeing limited or no connectivity. If i connect the modem directly to the pc i get internet access so i think it might be some problem with the configuration of the router. The router is cisco and the PC is a XP. Could someone please help me?

Thanks

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Comments

RTmarc

How is the internal interface of the modem configured? Is DHCP enabled on that end (most likely yes). Can you set that to manual and then configure the interface on the Cisco router appropriately?

networker050184

What have you done besides just setting up DHCP? It takes a little more than that. You are going to need some routing set up to tell the packets where to go. They aren't magic you know

thickSkin

sorry networker050184

i should have given more details. I have set up routing using rip. I also did the NAT translations in which i configured the outside interface to receive an ip address dynamically. I entered a static address for my pc and used my ISP's DNS servers address. I created a default route to get to the ISP using the IPS's default gateway as the next hop address.

I hope this is adequate information to help remedy the problem.

jason_lunde

I have had the same problem dude. Unplug your router, and then your modem- like take the power cords off. Leave them unplugged for at LEAST 5 minutes. This will clear any learned mac addresses on the modem. (I know, this sounds stupid!). Then plug in your modem...let it boot up. Then plug in your router. If your router config is good, this should fix the problem. This is the advice I got from a comcast engineer on the matter, and it worked like a charm. I once, long time ago, had a cable modem----linksys router. When I got my first cisco, configured it, and nothing worked. Did this little trick, and it came right up. Hope this helps.

mella060

Have you created the dialer interface on the router to set it up as a pppoe client ?

I am currently using a cisco 871 with my DSL connection. I have the router connected to the DSL modem which is running in bridge mode.

You don't need to use RIP. Just use a default route that points to the dialer interface.

ip route 0.0.0.0 0.0.0.0 Dialer0

Have you created the access list to go with the NAT statement ?

thickSkin

Thanks

Did some more troubleshooting the problem was that the interface on the router that connects to the modem was down.

bgrablin

You could use:

Router#clear arp

On the router.

Too bad their isn't a similar command and ability for the modem.

jason_lunde

thickSkin wrote: »

Thanks

Did some more troubleshooting the problem was that the interface on the router that connects to the modem was down.

That would do it

Mark Knutson

jason_lunde wrote: »

I have had the same problem dude. Unplug your router, and then your modem- like take the power cords off. Leave them unplugged for at LEAST 5 minutes. This will clear any learned mac addresses on the modem. (I know, this sounds stupid!). Then plug in your modem...let it boot up. Then plug in your router. If your router config is good, this should fix the problem. This is the advice I got from a comcast engineer on the matter, and it worked like a charm. I once, long time ago, had a cable modem----linksys router. When I got my first cisco, configured it, and nothing worked. Did this little trick, and it came right up. Hope this helps.

This is the case for my cable modem as well--had to power it many timesin the various configurations of linux and cisco firewalls I played with.

Comcast told me they will only give out one ip address at a time, and the only way to trigger that is to power down the cable modem. The engineer told me they have lots more customer problems since they switched from two addresses per customer to one.

captobvious

thickskin wrote: »

thanks

did some more troubleshooting the problem was that the interface on the router that connects to the modem was down.

doh!