Fixed Ethernet interfaces on 2621 both on the same subnet? Possible?

[manolias]

Hi,

This is a bit tricky.

1) Is it possible to configure both of the fixed ethernet ports on a 2621 router to be connected to the same subnet?

i.e

interface Ethernet0/0

ip address 192.168.3.8 255.255.255.0

interface Ethernet0/1

ip address 192.168.3.18 255.255.255.0

2) Once this is done is it possible to configure a second router in the same way and implement HSRP between the two routers?

My goal is to set up a Redundant LAN that duplicates all hardware (2 switches, 2 routers, 2WAN links) but only contains one single LAN subnet. For each of the LAN hosts I am using two special network adapters that support "Fault Tolerance" whereby a failure in one cable or one of the switches is automatically detected by the network interface and then the standby interface is started. I am basically trying to do the same thing on the routers.

Thanks in advance.

AM

[milan.kulik]

Hi,

ad 1) it's impossible, the IOS will not allow you to use the same subnet on different interfaces.

ad 2) Why don't you just configure two HSRP routers each connected to your LAN via one Ethernet port to a different switch using HSRP standby track to monitor WAN links?

see http://www.cisco.com/warp/customer/619/6.html

or http://www.cisco.com/cgi-bin/Support/PSP/psp_view.pl?p=Internetworking:HSRP

Regards,

Milan

[manolias]

Hello,

Thanks for the response.

Regarding question 2) I cannot do it in the way that you suggested because the backup router has slow dial-up links and I do not want to failover to this router when the switch that the main router (fast WAN link) is connected to fails.

If the switch that the main router is connected to fails, I would like packets to be redirected to the main router through the other switch.

Any more ideas?

Thanks again & regards,

A.

[ji.xie]

How about IRB ?You can configure a briege group and the two ethernet in the same group ,and the ip add is added to the bridge group.