NE40 Version: VRP (R) software, Version 3.10, RELEASE 2351
MOB network requires configuring of DHCP functionality because the amount of hosts exceeded that of the available IP addresses.
DHCP client and DHCP server are in different subnet, so we need to configure DHCP relay. The LAN clients communicate and obtain IP addresses from DHCP server on other subnet through DHCP relay. The LAN clients first connect with CISCO switch and than with KHI_NE40.
We need to configure DHCP relay functionality on FSD_NE40 and KHI_NE40. After configuration we find that clients connected with FSD_NE40 is working fine but clients connected with KHI_NE40 obtained IP other than the IP’s which we assign on DHCP server. We also find that sometimes clients at KHI_NE40 got correct IP but most of the time it got the IP from DHCP server which we did not configure.
During troubleshooting we find that DHCP clients (connected with KHI_NE40) send discover messages to DHCP server and sometimes it receives offer message from one DHCP server and most of the times it receives offer message from other DHCP server which we did not configure.
We asked the customer that is there any DHCP server running in a local network ? customer says that yes there is DHCP server configured locally. One which we configured and the other which customer created locally for other topology and informs us that none of the client is using DHCP server which they created on local network.
Than we disconnect the cable from Cisco LAN switch which is connected with the local DHCP server. After that step problem was resolved.
Kindly find the attached configuration on KHI_NE 40 and FSD_NE40.
Also the Debug file of KHI_NE40 and topology diagram.
The cause of the problem is that in past customer configure DHCP server on their local network, so When a DHCP client at KHI_NE40 initializes DHCP, it first broadcasts the configuration request packet in a local network, and the DHCP server on the local network respond to DHCP Clients and the DHCP relay was not used. After disconnecting that local DHCP server from Cisco LAN switch problem was solved.