Technical data

Configuring the DHCP Server
7.4 Configuring the DHCP Server
7.4.4 Returning to the BOOTP-Only Configuration
You can return to a BOOTP-only configuration at any time. Further, you can
use the previous TCPIP$BOOTP.DAT database file and the client entries it
contains. If you deleted the TCPIP$BOOTP.DAT file, you can create a new one
and populate it with entries (see Section 9.5).
To enable BOOTP after you have configured your host for DHCP, run
TCPIP$CONFIG and enable the BOOTP component from the Server Components
menu. Your existing DHCP files will remain for future use.
7.4.5 Setting Up a DHCP Cluster Failover Environment
You can set up an OpenVMS Cluster environment for DHCP server failover. In
this environment, a standby system becomes the DHCP server if the active DHCP
server process fails or is stopped, or the system on which it is running fails or
shuts down.
With cluster failover, the DHCP server uses the OpenVMS lock manager during
process initialization to acquire a system-level, exclusive-mode lock on a resource
called TCPIP$DHCP_SERVER. The first server started on the cluster obtains the
lock on TCPIP$DHCP_SERVER and becomes the active DHCP server. The other
DHCP servers wait to obtain the lock and become the standby servers.
When the active DHCP server process exits for any reason, the lock on
TCPIP$DHCP_SERVER is released and one of the standby processes acquires the
lock and becomes the active server.
To configure the DHCP server failover environment, do the following:
1. If the DHCP server is running on one of your systems, manually disable it by
entering the following command on the server system:
$ @SYS$STARTUP:TCPIP$DHCP_SHUTDOWN.COM
2. Create a directory for the DHCP configuration and binary database files
that is visible to the DHCP cluster members. Specify TCPIP$DHCP as the
directory’s owner. For example:
$ CREATE/DIRECTORY/OWNER=TCPIP$DHCP WORK1$:[DHCP_CONFIG]
3. If you have already been running DHCP server and want to start with the
existing data files, then do the following:
a. Copy the DHCP data files from the DHCP directory to TCPIP$DHCP_
CONFIG:*.* by entering commands similar to the following:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]DHCPCAP. TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]DHCPTAGS. TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]NAMEPOOL. TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]NETMASKS. TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]NETS. TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]SERVER.PCY TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP]DB%.%%% TCPIP$DHCP_CONFIG:
$ COPY SYS$SYSDEVICE:[TCPIP$DHCP].DDNSKEYS TCPIP$DHCP_CONFIG:
Configuring the DHCP Server 7–21