[c-nsp] Native VLAN and DHCP

[Chris Gotstein]

Got lots of good suggestions.  Tried adding "spanning-tree portfast
trunk" and that definitely helps the the AP get the correct IP address
from the native VLAN, but as soon as i add in a second AP, i get a
spanning-tree loop and one of the ports gets disabled.  If i remove the
command above, then i get random IP addresses from different VLANs.

---- ---- ---- ----
Chris Gotstein, Sr Network Engineer, UP Logon/Computer Connection UP
http://uplogon.com | +1 906 774 4847 | chris at uplogon.com

On 4/30/2010 8:42 AM, Chris Gotstein wrote:
> According to HP, the dhcp request is untagged.  I will try running a
> sniffer to see what's going on.
> 
> The controller is acting as the DHCP server on vlan 3 just for the APs.
>  I had also tried using the MS DHCP server for the APs, but that had the
> same results as well.
> 
> On 4/30/2010 6:04 AM, Arie Vayner (avayner) wrote:
>> Chris,
>>
>> To my understanding, this should work...
>> Are you sure the AP is sending the DHCP request untagged?
>> BTW, you mentioned the AP is acting as DHCP *server* - is it server or
>> client?
>>
>> I would suggest that you just SPAN the port of the AP and put a sniffer
>> on it so you can see what is going on during the boot up process.
>>
>> Arie
>>
>> -----Original Message-----
>> From: cisco-nsp-bounces at puck.nether.net
>> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Chris Gotstein
>> Sent: Friday, April 30, 2010 00:33
>> To: cisco-nsp at puck.nether.net
>> Subject: [c-nsp] Native VLAN and DHCP
>>
>> I've got a WS-C3560G-24TS switch doing L3.  We are running multiple
>> VLANs, each VLAN has it's own subnet, and the clients are getting their
>> IP addresses from a MS DHCP server using ip helper-address command for
>> each VLAN interface.
>>
>> Problem:
>>
>> Setting up HP access points and controller.  Want to use VLAN 3 as the
>> native VLAN for the HP APs.  Port that the AP is connected to is
>> configured as the following:
>>
>> interface GigabitEthernet0/13
>>   description Connect to HP AP
>>   switchport trunk encapsulation dot1q
>>   switchport trunk native vlan 3
>>   switchport trunk allowed vlan 3,10,20,25,100
>>   switchport mode trunk
>>
>> The controller is acting as the DHCP server, which is also on VLAN 3.
>> But when the AP boots up, it takes a long time for it to get an IP
>> address, and when it does finally get one, it's from a random VLAN of
>> the listed allowed VLANs, and not from VLAN 3.  I'm not sure if i'm
>> missing something or if i'm just unable to use the native vlan command
>> in this fashion.  Any advice?  Thanks.
>>
>