Access point not getting DHCP in the right VLAN

[MartinBlak]

Hi,

I have 3 Access points that are behaving very strange.

They got a DHCP address in the wrong VLAN, and after changing the switchport access vlan they get no adress.

If i change the switchport back to the original VLAN they once again get a DHCP adress.

I have tried:

Rebooting the AP's (same problem)

clearing the AP config and rebooting (same problem)

Setting up a static ip adress for the AP, this works, then tried to set it back to dhcp while in same vlan (same problem)

Cleared the IP arp entry for that adress on the switch that has the SVI (same problem)

The SVI is configured with an IP helper to our central DHCP servers.

Hope you can help me.

[Leo Laohoo]

What APs are these?

[MartinBlak]

It's 2: 1562E and 1: 3802I

[Sandeep Choudhary]

if these APs are in loclal mode then you must configure swicth port as access!

Check the DHCP scope again.

[MartinBlak]

The APs are indeed local and the switchport is configured as access. The DHCP scope has alot of free adresses so this shouldn't be a problem either. We have 80+ APs in the same subnet distributed over this specific location.

[Leo Laohoo]

If the APs are not getting IP addresses, are they suddenly appearing to have IP address that are 6.X.X.X?

[MartinBlak]

I can see via CDP, that they get an IPv6 address.

They get no IPv4 addresses.

When the switchport is set to vlan 1 they get an ip like 10.1.X.X and when i set the VLAN to 500 get none. They should get and address like 10.5.X.X.

Entry address(es):
IPv6 address: XXXXXXX (link-local)

[Sandeep Choudhary]

chekc if there is any mis-configuration regarding Native vlan on siwtch side.

[MartinBlak]

The switch has uplink to our 2 routers. Both interfaces are correctly configured, native vlan and the rest.

[Sandeep Choudhary]

can you configure helper command under AP mgmt VLAN and try again

Example:if AP mgmt vlan is 5 then use this config:

Config t

Interface vlan 5

ip helper-address <DHCP server IP>

Regards

Dont forget to rate helpful posts

[MartinBlak]

As i wrote in the original post: "The SVI is configured with an IP helper to our central DHCP servers." so this is already done.

[patoberli]

Can you connect a laptop into the same switch and VLAN and check if the laptop gets a correct IP address?
If not, then the issue lies on the switch/router/dhcp side.

[MartinBlak]

This is a really good question, i can't get a PC in one of the ports, but i can try and configure a SVI on the specific VLAN and set the IP to DHCP. I will try this.

[MartinBlak · Accepted solution]

I have now after trying to create the SVI for the relevant VLAN concluded that i had forgotten to configure "IP DHCP SNOOPING TRUST" on the uplink ports. Thank you for all your different ideas.

[ToddRihn96727]

Having the same issue.  Some AP are working fine, but 4 others are not receiving IP addresses.  They are coming up with a 6.x.x.x. address.  Is this like the APIPA address for windows?  We have configured a local pool on the switch to bypass the DHCP server, but that still does not work.  

Any suggestions would be appreciated.

Thanks