Trouble shooting: Cisco router DHCP No option 125

Posted on November 13, 2013



Configure DHCP on Cisco router 2811 to assign a static IP to the italkBB: Cisco SPA 1202.

  1. start DHCP service by command:

    service dhcp
  2. debug on Cisco router to check DHCP request by the commands:

    debug ip dhcp server packet
    terminal monitor

    Debug info :

    DHCPD: DHCPREQUEST received from client 0100.1c23.3541.98
  3. configure DHCP

    ip dhcp pool ItalkBB
        host //no mask configured, IP’s class mask assigned
        client-identifier 0100.1c23.3541

    But italkBB can’t get IP from Cisco router 2811, and the error msg in debug info is:

    DHCPD: client’s VPN is .
    DHCPD: No option 125

    Checked DHCPREQUEST on Cisco Router in debugging mode:

    DHCPD: DHCPREQUEST received from client 0100.1c23.3541.98
  4. change client-identifier by command:

    client-identifier  0100.1c23.3541.98

ItalkBB works.

Note: from my understanding, the MAC of the iTalkBB should be ‘0100.1c23.3541’, in fact, the suffix: ‘.98’ is required as a part of the identifier.

The basic config file for configuring DHCP SERVER on Cisco router

service dhcp
no ip dhcp conflict logging
ip dhcp pool 1
interface GigabitEthernet0/1
 ip address

A case from blog : Embedded System Testing Blog

“No option 125” error from Cisco DHCP server Problem : “No option 125” error was continuously repeating and DHCP Server on Cisco was not offering any IP address to the clients.

Jul 24 05:36:21.147: DHCPD: No option 125 Jul 24 05:36:21.147: DHCPD: DHCPDISCOVER received from client on interface GigabitEthernet0/1. Jul 24 05:36:30.707: DHCPD: client’s VPN is . Jul 24 05:36:30.707: DHCPD: No option 125

> Solution: After some debugging, came to know that the problem is with the subnet configured on the Gigabit ethernet. For DHCP Server to offer the IP address at least one interface should be in the same network as the pool is defined. Once the subnet is properly configured, the Server started replying.

Trouble shooting: Cisco router DHCP No option 125


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