topic Hi Martin, in Wireless

interface configuration not possible

mshemon123 — Mon, 05 Jul 2021 13:38:32 GMT

Hi all,

We are on the way to replace our existing 4402 controller with a 5508 one.

at the moment there is a problem with configuring some interfaces.

1. there is an management interface with a static IP , lets say 192.168.158.17 / subnet: 255.255.192.0 / Gateway 192.168.191.254 / VLAN 30

2. there is annother dynamic interface with an static IP, lets say 192.168.178.10 / subnet: 255.255.254.0 / Gateway 192.168.178.1 / VLAN 100

The Controller tells me, that it is not possible to configure overlapping subnets. I understand this, and as i read inside the documentationthis is true.

But: these networks are on different VLAN´s and , these are 2 completely different Networks.

additional: this cconfiguration is possible on the 4402 controller without any problems.

Question: is it possible to override this warning and why is the controller ignoring the VLAN tag. I understand that is not possible to have two overlapping net´s inside the same VLAN but i dont understand why this is not possible in different VLAN.

Any Ideas?

regards

Martin

Hi Martin,

Rasika Nayanajith — Fri, 03 Mar 2017 03:25:18 GMT

Hi Martin,

1. there is an management interface with a static IP , lets say 192.168.158.17 / subnet: 255.255.192.0 / Gateway 192.168.191.254 / VLAN 30

If you typed it correctly,192.168.158.17 with mask of 255.255.192.0 is a super large network.

Network address is 192.168.128.0/18 and valid host from 192.168.128.1 to 192.168.191.254.

So 192.168.178.0/23 network will be overlapping with it.

Pls check the first subnet mask is right

HTH

Rasika

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Hi Rasika,

mshemon123 — Fri, 03 Mar 2017 14:30:32 GMT

Hi Rasika,

you are right. The netmask is correct. and the other is also correct.

but: the Networks are on different VLAN ! So they dont see each other and have no direct contact.

Inside the 4402 Controller it is possible to configure and inside the 5508 it is not.

Why the Controller ignores the VLAN ! Setting ?

Regards

Martin

Hi Martin,

Rasika Nayanajith — Fri, 03 Mar 2017 19:38:53 GMT

Hi Martin,

inside the 4402 Controller it is possible to configure and inside the 5508 it is not.

may be 4402 is not intelligent enough to check this.

Why the Controller ignores the VLAN ! Setting ?

You should not configure any overlapping IP addresses in any cisco device (router, switch, wlc, ect). In fact Cisco devices should not allow you to do this, even you configure it by mistake.

vlan number is not the important bit here. IP subnet is the key.

Note: you can mark the thread answered, if given response clarify your doubts.

HTH

Rasika