Problem : "No option 125" error was continuosly repeating and DHCP Server on Cisco was not offering any IP address to the clients.
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Jul 24 05:36:21.147: DHCPD: No option 125
Jul 24 05:36:21.147: DHCPD: DHCPDISCOVER received from client 001e.e5dc.ae.c0 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
Jul 24 05:36:21.147: DHCPD: DHCPDISCOVER received from client 001e.e5dc.ae.c0 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
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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 ipa ddress atleast one interface should be in the same network as the pool is defined. Once the subnet is properly configured, the Server started replying.
The basic config file for configuring DHCP SERVER on Cisco router
service dhcp
no ip dhcp conflict logging
!
ip dhcp pool 1no ip dhcp conflict logging
!
network 11.0.0.0 255.0.0.0
default-router 11.0.0.1
!
interface GigabitEthernet0/1
ip address 11.0.0.1 255.0.0.0
