Technical data
Configuring SNMP
13.1 Key Concepts
TCP/IP Services provides an SNMP master agent, two subagents (MIB II and
Host Resources MIB), a MIB converter and compiler, a simple MIB browser, and
MIB utility programs. Each subagent contains routines that perform read and
write operations on its MIB data items.
Table 13–1 describes the SNMP components and the sample code supplied for
custom subagent development.
Table 13–1 SNMP Components
Component Description
Master agent
SNMP Version 2
Process name: TCPIP$SNMP_n, where n is the number of
times that the master agent has been started since the SNMP
service was enabled.
Keeps track of managed objects and allows objects to register
themselves. Sends information about these objects to remote
SNMP management consoles. Also maintains a small set of
variables for the MIB II component.
MIB II Process name: TCPIP$OS_MIBS.
Provides information about the TCP/IP protocol stack and
other network activity.
Host resources MIB Process name: TCPIP$HR_MIB.
Provides information about the host system.
MIB converter Extracts a MIB definition in ASN.1 notation into a MIB
definition (.MY) file.
MIB compiler Compiles MIB-definition files (for example, CHESS_MIB.MY)
into source code templates for use in building subagents.
SNMP utility programs Acts as a simple clients to obtain a set of values for a MIB and
to listen for and send trap messages. For information about
using the MIB utility programs, see the Compaq TCP/IP
Services for OpenVMS SNMP Programming and Reference
guide.
SNMP subagent
example
Implements an example based on the chess game; includes
executable and source code.
13.1.1 Understanding How SNMP Operates
The TCPIP$CONFIG procedure sets up the SNMP UDP-based service at well-
known port 161.
In addition, TCPIP$CONFIG sets up required files in the
SYS$SYSDEVICE:[TCPIP$SNMP] directory.
The SNMP startup procedure (SYS$STARTUP:TCPIP$SNMP_STARTUP.COM)
runs from the general TCPIP$STARTUP.COM procedure or can be run directly
by the system manager.
TCPIP$SNMP_STARTUP.COM does the following:
1. Checks the TCP/IP Services license and enables the SNMP service.
2. Installs images with the required privileges (as appropriate: BYPASS,
PHY_IO, and WORLD).
3. Runs SYS$STARTUP:TCPIP$SNMP_SYSTARTUP.COM.
13–2 Configuring SNMP