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Multiple DHCP Scopes associated with VLANs

Hi there, First of all I'm from Switzerland. Therefore I'm pre-sorry for my bad english.

My Problem is the following: I'm trying to set up an Cisco 1231 AP (IOS 12.3). I configured (with the GUI) an SSID 'intern' associated with the VLAN 250. Now I got the two new virtual Interfaces Dot11radio0.250 and FastEthernet0.250. They are both in the 'bridge-group 250'. The physical interface 'Dot11radio0' itself is in the 'Bridge-group 1' as well as the physical interface FastEthernet0.

Now I configured these DHCP Scopes like that:

ip dhcp excluded-address 10.1.0.1 10.1.0.2 ip dhcp pool INTERN network 10.1.0.0 /28 lease 10

ip dhcp excluded-address 10.0.0.1 10.0.0.3 ip dhcp pool DEFAULT network 10.0.0.0 /28 lease 10

The following IP settings are set: Dot11radio0: no ip address Dot11radio0.250 : 10.1.0.1 /28 FastEthernet0: no ip address FastEthernet0.250: no ip address BVI 1: 10.0.0.2 /28

Now when I try to connect to the AP using the SSID 'intern', I get no IP-Address.

I even tried to configure a BVI 250 interface with the IP-Address

10.1.0.2 /28, it doesn't help. On the AP I turned on all 'debug ip dhcp server' stuff and I don't even see a DHCPDISCOVER. I also tried to abstract the Dot11radio0 interface from the bridge-group 1 which isn't allowed as the AP says.

Probably I don't understand the Bridge-group thing very well but isn't it inconsistent when the 'root' interface dot11radio0 is in bridge-group 1 and the sub-if dot11radio0.250 itself is in bridge-group

250?

I tried one more thing: I did exactly the same configuration (in the GUI) without assigning the SSID 'intern' to a VLAN. In that case I get an IP Address out of the DEFAULT Pool.

Reply to
bck
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Hi bck,

~ Hi there, ~ First of all I'm from Switzerland. Therefore I'm pre-sorry for my bad ~ english.

No worries; it's much better than my French, German and Italian all put together.

Let me explain that the Cisco Aironet APs have the following configuration restriction: they may have exactly one IP address, which IP address must be configured on interface BVI1. And, if you have configured VLANs, BVI1 must be in the native VLAN.

So, to support IP traffic on multiple VLANs through the AP, the AP's LAN interface must be connected (as an 802.1q trunk) to a switch/router which is capable of routing (or otherwise talking IP) on those VLANs.

It is possible to configure the DHCP server in the AP to serve up addresses in multiple subnets; however, since the AP only has an IP presence in the native VLAN, only the native VLAN scope will work, UNLESS you have configured your interVLAN router to forward the DHCP requests from non-native VLANs to the AP.

This article may help to explain matters:

Using VLANs with Cisco Aironet Wireless Equipment

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Regards,

Aaron

Reply to
Aaron Leonard

Oh thank you very much. You probably saved me alot of time! Well, I'll try another approach:

DHCP Server on a router and all the devices connected together on a

2950.

Regards, Thomas

Reply to
bck

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