WLC4402 DHCP/BOOTP

Lasse.Pekka · ‎03-28-2007

Does WLC4402 (sw 4.0.206.0) act as BOOTP relay? When I use

Windows DHCP server using only BOOTP the client does not get address. DHCP works fine. Allso when I use dhcp pool from Catalyst 6500, client does not get address.

didyap · ‎04-03-2007

Yes, WLC acts a DHCP Relay(Boot Strap Relay) device. This is the sequence of events that occur.

This is the sequence of events that occur:

The WLAN client sees the administration-defined virtual address as the DHCP server address. The recommended address is usually 1.1.1.1 because this address is not normally a routable network address.

The WLC shows the virtual address to the WLAN clients and the management interface address upstream.

The WLC acts as a DHCP relay (Bootstrap Protocol [BOOTP] relay) device.

Darren Ramsey · ‎04-03-2007

Actually it functions as a DHCP proxy by default, but is configurable.

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Wireless%20-%20Mobility&topic=General&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddbf63d/3#selected_message

Lasse.Pekka · ‎04-03-2007

I have tried to disable dhcp proxy, but it does not have affect to getting address.

here is debug from catalyst:

DHCPD: DHCPDISCOVER received from client 0100.0b7d.1561.7f through relay 10.1.1.2

DHCPD: Sending DHCPOFFER to client 0100.0b7d.1561.7f (10.1.1.10).

DHCPD: unicasting BOOTREPLY for client 000b.7d15.617f to relay 10.1.1.2

DHCPD: DHCPDISCOVER received from client 0100.0b7d.1561.7f through relay 10.1.1.2

DHCPD: Sending DHCPOFFER to client 0100.0b7d.1561.7f (10.1.1.10).

DHCPD: unicasting BOOTREPLY for client 000b.7d15.617f to relay 10.1.1.2.

Catalyst have vlan interface 1500 whitch address is 10.1.1.1 the Controller is directly connected to Catalyst.

Here is the deug of controller:

00:0b:7d:15:61:7f dhcpProxy: Received packet: Client 00:0b:7d:15:61:7f

DHCP Op: BOOTREQUEST(1), IP len: 300, switchport: 29, encap: 0xec03

00:0b:7d:15:61:7f dhcpProxy: dhcp request, client: 00:0b:7d:15:61:7f:

dhcp op: 1, port: 29, encap 0xec03, old mscb port number: 29

00:0b:7d:15:61:7f Determing relay for 00:0b:7d:15:61:7f

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 10.1.1.2 VLAN: 1500

00:0b:7d:15:61:7f Relay settings for 00:0b:7d:15:61:7f

Local Address: 10.1.1.2, DHCP Server: 10.1.1.1,

Gateway Addr: 10.1.1.1, VLAN: 1500, port: 29

00:0b:7d:15:61:7f DHCP Message Type received: DHCP DISCOVER msg

00:0b:7d:15:61:7f op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1

00:0b:7d:15:61:7f xid: 4161094549, secs: 7168, flags: 8000

00:0b:7d:15:61:7f chaddr: 00:0b:7d:15:61:7f

00:0b:7d:15:61:7f ciaddr: 0.0.0.0, yiaddr: 0.0.0.0

00:0b:7d:15:61:7f siaddr: 0.0.0.0, giaddr: 10.1.1.2

00:0b:7d:15:61:7f DHCP request to 10.1.1.1, len 350, switchport 29, vlan 1500

00:0b:7d:15:61:7f Determing relay for 00:0b:7d:15:61:7f

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 10.1.1.2 VLAN: 1500

Thanks for your answers

zhenningx · ‎04-04-2007

It looks like you are hit by a bug discussed before:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Wireless%20-%20Mobility&topic=General&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.1ddbc8c9

zhenning