The following describes the behavior of DHCP service with multiple IP service addresses.
DHCP service requires at least one IP address on a service interface (eth0, a VLAN interface, or bond0). If multiple IP addresses are configured on a service interface, DHCP will use the first IP assigned to the interface for service by default.
Note: You can view the order of IP addresses assigned to an interface by connecting to your DNS/DHCP Server via SSH and running the ip address command.
- If you have configured DHCP on a service interface with multiple IP addresses, you must
set the Server Identifier DHCP Service option for one of the IPs on the interface. This
will let DHCP know on which IP address to listen and provide service to clients.Note: As a best practice, BlueCat advises all customers running multiple IP addresses on any interface to use the Server Identifier DHCP Service option to ensure proper communication with DHCP clients.
- If you want to use a VLAN interface or bonding interface strictly for DHCP service, you must configure at least one IP address on that interface. If no IP addresses are configured on the service interface, DHCP won't listen on that interface to provide service to clients.
- If deployable DHCP ranges match two or more service IP addresses from unique subnets on a single service interface, you need to create a Shared Network for these DHCP ranges in order to deploy DHCP successfully. This is due to how DHCP service handles deployment through interfaces. For more information refer to Shared networks.