WLC 5508 internal DHCP problem

[satya mothukuri]

Hi All,

I have a query in the configuration. Please comment on the same.

Please find the below configuration. The two controllers are having two internal DHCP servers with the same range in LAN (enx1,enx2).

but i have specified which is primary DHCP server(enx3) in WLAN interface.

Now if a new user added into network, will he get IP address from primary dhcp(WLC) or AP connected WLC.

if two users connected to 2 diff AP's which are connected to 2 WLC will get the same IP address? since having same address pool configured.

Please find the attached config.

Regards,

Satya.M

[satya mothukuri]

Please reply....

Regards,

Satya.M

[Nicolas Darchis]

As stated in the configuration guide :

-You cannot rely on the internal DHCP scope in multi-WLC configuration

-You cannot have teh same DHCP subnet range on several WLCs because they do not communicate on which ip was allocated

[satya mothukuri]

Thanks for your reply Nicolas...

Now i just want to know the users connected to the WLC1 and WLC 2 will get diff diff ip address r same ip address to result in IP conflit

Regards,

SAtya.M

[Nicolas Darchis]

well the above says it all. Users from different WLC might end up with the same ip address and create a conflict.

That's why it's not supported. :-)

[satya mothukuri]

Please let me know wt is the information about dhcp in interface??

Regards,

Satya.M

[Nicolas Darchis]

Well. The first line defines the primary DHCP server and the second line the secondary DHCP server ...

in case the primary doesn't answer for dhcp request, the secondary is tried. It's not a load-balancing system.

[satya mothukuri]

Thanks ...let me be more clear....

now in my wlc1 and wlc 2 if i c the clients list.....few of them have same ip address. i want to know where the problem is?

[Nicolas Darchis]

What don't you understand in "configuring internal dhcp scopes on several WLC is NOT SUPPORTED" ?

A WLC cannot know what ips the other WLC already handed over and a WLC cannot serve ips for clients that are located behind another WLC. So obivously you have conflicts !!!

[satya mothukuri]

Thanks for ur reply.....

if in all the dynamic interfaces of 2 wlc, i menction primary dhcp address as single address

ex:

in wlc 1

    dynamic1

    primary dhcp 10.54.50.41

    dynamic2

    primary dhcp 10.54.50.41

in wlc 2

dynamic1

    primary dhcp 10.54.50.41

    dynamic2

    primary dhcp 10.54.50.41

will this solve issue? can i get ip address from singlr dhcp server?

Regards,

Satya.M

[Nicolas Darchis · Accepted solution]

this eliminates the duplicate ip problem.

But as I said 4 times now :

"a WLC cannot serve ips for clients that are located behind another WLC"

So putting in WLC2 the ip of WLC1 as dhcp server is NOT SUPPORTED

[satya mothukuri]

thanks a lot....i was saying the same thing to my boss.....but he is not able to understand.

now with this i ll try.

Thanks a lot.

Regards,

Satya.M