How do I route traffic to the Internet through Switch?

[Ignat Sitnikov]

Here is my topology. I have a cisco 2612 (one Ethernet port) hooked up  to catalyst 2960. Cable modem is hooked to that switch as well. I have  configured vlans and DHCP pool on a router, as well as dns. My problem  is that I don't know how to route traffic out of interface on a switch. I  understand that my local pcs that connected to a switch go first to the  router since its the default gateway but I dont know how to send that  traffic out of switch to reach the Internet. I am running EIGRP on the  router by the way. Everything works on the Lan but I can't get out to the internet. I understand I need NATs to be able to use the same global outside ip for all my Pcs, but at this point I just want to be able to ping Internet from one station. Please help me figure out how do I route traffic back to the switch and out to the INternet.

[Roman Rodichev · Accepted solution]

Привет

- Create new public VLAN on the switch and put Cable Modem port in it

- Convert the port on the switch where the router is connected from a vlan port to a trunk port and trunk internal and public VLAN to the router

- Create new subinterface on the router for the public VLAN

- Put ip address dhcp on that subinterface so that your router gets an IP from the cable modem

- Configure nat on the router where internal subinterface is nat inside and external subinterface is nat outside

Or you can just connect the cable modem directly to the second interface on the router instead of connecting it to the switch

[Ignat Sitnikov]

Spasiba!!! Yeah I know usual set up would be modem>router>switch...but i got only 1 interface on a router...I am thinking about dishing out 35 bucks and getting a 4 port fast ethernet WIC :-) I just have to make sure it will work on my old 2612.

[Ivan Krimmel]

Hi there,

I think with a single interface on a router one could opt for the old Router-on-a-Stick setup, though dot1q tags will be utilized.

Cheers,

Ivan.

[Ignat Sitnikov]

That's what i figured. I just didn't have the public Vlan pull ips from DHCP. I didn't realize thats hows its done. It wasn't in my CCNA study guide book :-). Thank you gentleman!

[Ivan Krimmel]

Пожалста! :)