How to configure multiple LAN ports on the router with the same gateway

[lauraseymore]

Hi all,

I have 2921 router and I have 3 very basic switches that I need to connect to the router. The switches have very basic default configurations and there is no way to edit them, so I only have one VLAN and one default gateway. I can't assign the same IP address to each LAN port. Can any one help me with settings I need? I'm not sure how to make this setup work...

Thanks,

LS

[vmiller]

So, how do you set the default gateway of one switch ?

Worst case, daisy chain the switches, use one interface on the router.

get better switches .....

[lauraseymore]

The switches we currently have are plug and play. They are absolutely no way to configure them with default gateway.I don't think it is going to be a great idea plugging 2 switches into one because they are more switches pluged into those switches :-) lol... It is crazy and we are working on upgrading it. is there any better solutions? The network is a mess, at least we got a new router! :-D

[vmiller]

So, sounds like you need to just have all the workstations point to the router interface address as the default gateway and forget the switches.

is the router the DHCP server also ?

[lauraseymore]

Hi vmiller,

No router is not DHCP. We have DHCP server. But how will I configure router gateway IP, I have to configure IP on every port and I can't configure same IP those... See what I'm saying? Unless I can configure those 3 ports as layer 3 ports and see if it is going to let me configure 1 IP address for those 3 ports.... don't think it is going to work tho... :-(

[vmiller]

Correct, 1 vlan, 1 subnet, 1 gateway.

I'm no DHCP expert, but unless you can find a way to disciminate between different endstations, you are stuck.

[Gregory Snipes · Accepted solution]

Although this is not the best design and should be reworked in the future, what you want to do is posible using IRB.

Here is an example config for IRB:

interface FastEthernet0/0

bridge-group 1

!

interface FastEthernet0/1

bridge-group 1

!

bridge irb

!

interface BVI1

ip address 192.168.1.1 255.255.255.0

!

bridge 1 route ip

Notice that the physical ports do not have IP addresses on them, the IP for the subnet is on the BVI interface.

[lauraseymore]

Greg,

Thank you! I think this is exactly what I was looking for! Will try it now.

[Gregory Snipes]

Glad to help,

If this turns out to be a good solution for your issues, please remember to mark the solution correct so future forum browsers will know.

[lauraseymore]

Yes I will! Thank you!

[lauraseymore]

I'm not sure what is the issue is... But it does not seem to work. I can ping every thing from the outer but I can't ping anything from the work station. I can ping everything on the network. I can ping all of the interfaces on the cisco router but I can't ping anything else... any ideas...

[Gregory Snipes]

From what I read above you are saying that you can ping within the subnet an can ping all of the router interfaces, but cannot ping past the router. Is this correct? If this is the case, did you configure interface BVI 1 exactly as you had previously configured the SVI? If you are doing NAT on the router you would need to ensure you designate interface BVI 1 as "nat inside".

If you are not able to get this resolved, please post up a scrubbed config and I will have a look at it and verify the configuration.

[lauraseymore]

Gregory, just tested your settings and it does not work. thanks