Controller-less WLANs

How to configure DHCP option 242 on IAP

Introduction- This configuration feature of DHCP option  is available from Instant 3.3 and above.

  • The scope of the this feature is to allow users to add the DHCP options to the IAP.
  • The user configures the desired DHCP options for the DHCP profile with type and value.
  • This feature is valid only for local DHCP servers not for centralized L2, where DHCP server runs on the controller.

Feature Notes- 

  • User can add DHCP option 242 for bringing up the Avaya phones with the data VLAN, voice VLAN and TFTP server IP address.
  • Once this option is configured the Avaya phone will seek option 242 and the IAP will be able to serve this option with configured value.

Environment- Typical Environment of using any wired phones plugged into the network. In our example from network Topology you could see Avaya Phone is plugged into one of the switch port.

Network Topology- 

rtaImage.png

 

Configuration Steps- Configuration
-------------------
From UI go to More > DHCP Servers

rtaImage (1).png

 

The below debug commands only display the headers of DHCP packets exchanged between IAP and the Client.

rtaImage (2).png

 

Answer- From the above configuration we could notice DHCP option 242 configuration is applied successfully.

Verification- 

Commands to verify
---------------------------

show dhcp-allocation
show running-config

Troubleshooting- The below debug commands only display the headers of DHCP packets exchanged between IAP and the Client.

6c:f3:7f:c2:5d:fa# debug pkt type dhcp
6c:f3:7f:c2:5d:fa# debug pkt match type
6c:f3:7f:c2:5d:fa# debug pkt dump
Received packet from eth1 (timestamp 0219088168)
[asap_firewall_forward(3740):firewall entry] len 1038, vlan 0, egress CP, ingress eth1:
  #mac: etype 0800 smac b4:b0:17:7f:75:c9 tmac ff:ff:ff:ff:ff:ff
  #ip: sip 0.0.0.0, dip 255.255.255.255, proto 17, dont fragment, last fragment,
 fragment offset 0
    #udp: sport 68 dport 67 len 1004
      #dhcp: message-type: request
             hardware type: 1, len: 6
             hops: 0
             transaction id: be078b90
             seconds elapsed: 0
             boot flags: 0x0000
             client ip: 0.0.0.0, your ip: 0.0.0.0
             next server ip: 0.0.0.0, relay agent ip: 0.0.0.0
             client mac: b4:b0:17:7f:75:c9
             server host name: (null)
             boot file name: (null)
             magic cookie: 63825363

From the below screen shot you could notice the DHCP option 242 is configured.

rtaImage (3).png

 

Related Links- https://arubanetworkskb.secure.force.com/pkb/articles/HowTo/Debugging-DHCP-packets-on-Aruba-Instant-IAP
https://arubanetworkskb.secure.force.com/pkb/articles/HowTo/How-to-enable-packet-trace-to-debug-DHCP-packets-in-Instant-Access-Point-IAP

 

Version History
Revision #:
1 of 1
Last update:
‎04-02-2015 01:57 AM
Updated by:
 
Labels (1)
Contributors
Search Airheads
Showing results for 
Search instead for 
Did you mean: 
Is this a frequent problem?

Request an official Aruba knowledge base article to be written by our experts.