More then two IP-addresses on a interface. Possible???

[no46232]

I need to give a single interface on a Cisco 6509 three IP-adresses. Is this possible? Here's why:

I got three subnet routers(IBM 2210). They are all connected to another router(a IBM 8272). I am going to move the three routes from the 8272, away from the 2210, and over to a Cisco 6509.(Between these boxes, there are a an IBM router and a Catalyst 3548. These three routes from the 8272 need to go in on a single interface on the 6509.(The reason to that is that I eventually want to get rid of the 2210 routers, and put all the routes to the 2210, in to a single route from the 8272 to the Cisco 6509. But in the test fase I'm only going to do it in the configuration, and not physically move any cables or routers. And when I have configured three ip addreses on the singel interface on the 6509, I'm going to turn of the 2210's to see if it works)

Ornulf Lindblom

[johansens]

Hi Ornulf,

Yes it's possible. Use the "secondary" keyword at

the end of the "ip address" interface configuration command. This will also work with addresses on the same subnet as the primary address.

//Stig

[johan.den.hartog]

Hi, You can also configure sub interfaces.

No IP address on the real interface and ip addresses on the sub interfaces.

Good Luck !!

[zaushnyr]

I am not certain of you require the three subnets to be on the same broadcast domain (VLAN and MSFC VLAN Interface) or if they can be separate VLANs.

If you need them to be on the same physical network, VLAN, or broadcast domain, configure secondary IP Host addresses on the single MSFC VLAN interface for each subnet such as

!

interface VLAN1

description *** Multiple Subnet VLAN ***

ip add 10.1.1.1 255.255.255.0

ip add 10.1.2.1 255.255.255.0 secondary

ip add 10.1.3.1 255.255.255.0 secondary

!

If you want multiple VLANs, create a virtual interface for each subnet on the MSFC with appropriate IP host address, create the VLANs on the 6509, and put the ports of the connecting routers into their designated VLAN.

[htmltobing]

Yes, you can more than one ip address on single ethernet port, for example:

router(config-if)#ip add 10.1.0.1 255.255.0.0

router(config-if)#ip add 10.2.0.1 255.255.0.0 sec

router(config-if)#ip add 10.3.0.1 255.255.0.0 sec