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Working With DHCP in Oracle® Solaris 11.3

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Updated: October 2017

DHCP Clients With Multiple Network Interfaces

The dhcpagent daemon can simultaneously manage several different interfaces on one system. The interfaces can be physical interfaces or logical interfaces. Each interface has its own IP address and lease time. If more than one network interface is configured for DHCP, the client issues separate requests to configure them. The dhcpagent daemon maintains a separate set of network configuration parameters for each interface. Although the parameters are stored separately, some of the parameters are global in nature.

Global parameters apply to the system as a whole rather than to a particular network interface, for example, the host name, NIS domain name, and time zone. Global parameters usually have different values for each interface. However, only one value can be used for each global parameter associated with each system. To be sure that there is only one answer to a query for a global parameter, only the parameters for the primary network interface are used.

The dhcpagent daemon manages leases for logical interfaces and physical interfaces in much the same way. However, it does not manage the default routes that are associated with logical interfaces because the Oracle Solaris kernel associates routes with physical interfaces not logical interfaces. When a physical interface's IP address is established, you should place the necessary default routes in the routing table. If DHCP is used subsequently to configure a logical interface associated with that physical interface, the necessary routes should already be in place. The logical interface uses the same routes.

When a lease expires on a physical interface, the dhcpagent daemon removes the default routes that are associated with the interface. When a lease expires on a logical interface, the daemon does not remove the default routes associated with the logical interface. The associated physical interface and possibly other logical interfaces might need to use the same routes.