Setting up for DHCP with IPv4

6.10 LPAR mode z/VM guest

For connections through an OSA-Express adapter in QDIO mode configured with the layer 3 discipline, the OSA-Express adapter offloads ARP, MAC header, and MAC address handling.

Because a HiperSockets connection configured with the layer 3 discipline does not go out on a physical network, there are no ARP, MAC headers, and MAC addresses for packets in a HiperSockets LAN. The resulting problems for DHCP are the same in both cases and the fixes for connections through the OSA-Express adapter also apply to HiperSockets.

Dynamic Host Configuration Protocol (DHCP) is a TCP/IP protocol that allows clients to obtain IP network configuration information (including an IP address) from a central DHCP server. The DHCP server controls whether the address it provides to a client is allocated permanently or is leased temporarily. DHCP specifications are described by RFC 2131Dynamic Host Configuration Protocol and RFC 2132 DHCP options and BOOTP Vendor Extensions, which are available on the Internet at 
www.ietf.org
Two types of DHCP environments must be taken into account:
  • DHCP through OSA-Express adapters in QDIO mode
  • DHCP in a z/VM® VSWITCH or guest LAN
For information about setting up DHCP for a Linux® instance in a z/VM VSWITCH or guest LAN environment, see Redpaper Linux on IBM eServer zSeries and S/390®: TCP/IP Broadcast on z/VM Guest LAN, REDP-3596 at 
www.ibm.com/redbooks

The programs dhclient and dhcp are examples of a DHCP client and a DHCP server you can use. The distribution that you use might provide different DHCP client and server programs. For example, some distributions use the dhcpcd client program.