Two LAN Segments

[gvijayendran]

I have a 2620 router with single ethernet interface. I want to connect two different LAN segments to this router. How to do this ? Can anyone help me?

[konigl]

You basically set up a VLAN trunk port on the switch, and configure the single interface on your 2620 router to provide interVLAN routing via LAN sub-interfaces. How you do it depends on what kind of switch you are connecting the router to, either a switch running Cisco IOS or a switch running Cisco Catalyst OS. Here's two links:

Configuring InterVLAN Routing and ISL/802.1Q Trunking on a Catalyst 2900XL/3500XL/2950 Switch Using An External Router

http://www.cisco.com/en/US/tech/tk389/tk390/technologies_configuration_example09186a00800949fd.shtml

Configuring ISL and 802.1q Trunking Between a CatOS Switch and an External Router (InterVLAN Routing)

http://www.cisco.com/en/US/products/hw/switches/ps663/products_configuration_example09186a008014859e.shtml

Please note, to create and use sub-interfaces on a router such as the 2620, you will need a "Plus" version of IOS. And to be able to run "Plus" software, you may need more DRAM and flash memory.

Hope this helps.

[scottmac]

I believe you can also use the keyword "Secondary" to add additional addresses to a single interface.

Use the same syntax for ip addr on the appropriate interface, adding the word "secondary" (no quotes) to the end.

Not a good way to set it up (multinetting an interface) but sometime you gotta do what you gotta do. If you were planning on using this router for a firewall, don't use this for a firewall ... your system is exposed.

Good Luck

Scott