Cisco wireless controller and setting a static IP...

[Koldov]

I have had an issue where I cannot set a static IP for a laptop.

 

Our kit is all Cisco but managed by a 3rd party, so I called them to remote in and investigate (as the first and last 10 addresses in the VLAN rage should be available for static assignment). DHCP is managed by the core switch.

 

On the support call the engineer said that it appears that function is blocked (I didn't even know that was a thing)

by the wireless controller.

 

We had our whole network structure moved to a new IP address range by them in February and although the static ranges were implemented, nothing was mentioned about the fact that I couldn't actually use them as that functionality was blocked.

 

Here are the resolutions offered, do they sound feasible and (considering any future changes to this config would have to be done by the support company) which is my best option?

 

- There are a couple of approaches that can resolve the issue:

 

Could you find the MAC address for the Wireless Adapter (NIC)? For Windows it would be cmd > ipconfig /all > Wireless LAN adapter Wireless Network Connection: > Physical Address.

That way we can try to reserve the IP address on the core switch (the ip address will be within the dhcp range, but would bind to the MAC we specify).

 

alternatively:

- change the configuration on the Wireless Controller that would allow static IP addresses. Be aware there is a risk that if someone connected sets their IP to either the DGW or the controller address in that subnet, it can effectively act as a man in the middle attack. If you decide to proceed here, we will need the IP of the Wireless Controller.

Edited November 30, 2016 by Koldov

[pantscat]

Sounds like it's set to use "DHCP Secured IP Address Assignment" - basically to stop IP spoofing.

 

Option A sounds like the sensible approach - set a DHCP reservation for that MAC address.

[Koldov]

The thing is (to make it worse) the whole point of this exercise is to get the Head's MacBook (grrrrrr) to run SIMS through VMware Fusion.

 

I have had no luck in trying to get that on to the network and run SIMS, but I got some advice on here that both the MacBook and the virtual machine needed static IP's.

 

How am I going to do that? Will the virtual machine have a mac address?

 

Edit: Seems that I can set the VM's MAC manually, but to guarantee it will never change I have to mess around with the config file and hope I don't randomly choose one already on the network...

Edited November 30, 2016 by Koldov
Actually researched it lol!

[pantscat]

Not sure what difference static IPs will make (especially as you've indicated the static IP is on the same subnet as the DHCP range) - either it can talk to the SIMS or it can't.

 

Unless you've got some ACLs in place on the wifi network to prevent this...

[Koldov]

Not sure if we have any ACL's or not, I doubt it - but I didn't set the network up and have no access to it.

 

Anyone care to comment on how their wireless network is set up and if they implement 'DHCP Secured IP Address Assignment' or it's equivalent on other manufacturers wireless controllers?

 

Seems like the most sensible/secure route is plan A, but also needs the most configuration (isn't that always the way?) and it will stop me doing anything similar in the future without calling support.

 

About plan B....

 

Trying to think in risk assessment terms. How likely would it be that someone would come on site to a small Junior School with a device, hack the wireless key, find out the IP of the Wireless Controller, set up a man in the middle attack and start causing trouble?

 

Or could this be done remotely once in the network?