Allows access by the localhost system only
Provides information from the basic system MIB (Management Information Base)
Provides information from the extended UCD MIB for monitoring OS level parameters
Provides a CA Technologies MIB for monitoring services.

Open a privileged shell on your Gateway.

Stop the

snmpd

daemon:

# service snmpd stop

Generate a read-only user account for querying the SNMP information. Run the appropriate command, depending on whether you need to generate an encrypted or standard user account:

Encrypted Data User Command:
 
# net-snmp-config --create-snmpv3-user -ro -a MD5 -A 
<user password> -x DES -X 
<privacy password for data encryption>
<username>
 
Standard User Command:
 
# net-snmp-config --create-snmpv3-user -ro -a MD5 -A 
<user password> <username>

If you are using only the

Authentication Model

, comment out the settings for

View-based Access Control Model

(VACM). Follow these steps:

Open this file in a text editor:
/etc/snmp/snmpd.conf 
Add the '
#
' character to comment out all the
com2sec
entries. 

Restart the snmpd daemon:

# service snmpd start

When an SNMP Manager connects to the Agent, it presents a "community" name. For Gateway usage, the community is "l7" (lowercase "L"). The com2sec directive maps a community and IP source to a security name. In this case, only the

localhost

source is allowed. There are templates for a subnet and host security context.

sec.name        source          community
com2sec  localsec        localhost       l7
#com2sec subnetsec       192.168.1.0/24  l7
#com2sec hostsec         192.168.1.100   l7

The first matched combination of community and source (tuple) is used to define the security name. If none is found, then no security name is defined and access is denied.

Map the security names to groups with security models (v1, v2c or usm) using the

group

directive. You define a single group:

monitors

#       groupName      securityModel securityName
group   monitors        v1            localsec
group   monitors        v2c           localsec
group   monitors        usm           localsec
#group  monitors        v1            subnetsec
#group  monitors        v2c           subnetsec
#group  monitors        usm           subnetsec
#group  monitors        v1            hostsec
#group  monitors        v2c           hostsec
#group  monitors        usm           hostsec

Define the views that groups have access to:

You can refer to entities by their numeric OID or by a hierarchical name.

#       name            incl/excl       subtree         mask(optional)
# Present entire "system.*" tree from SNMPv2-MIB (.1.3.6.1.2.1.1)
view    systemview      included        system
# Present host.hrSystem.hrSystemUptime from HOST-RESOURCES-MIB (.1.3.6.1.2.1.25.1.1)
view    systemview      included        host.hrSystem.hrSystemUptime
# Present extended MIB from UCD-SNMP-MIB (.1.3.6.1.4.1.2021)
view    systemview      included        enterprises.ucdavis
#view   systemview      excluded        enterprises.ucdavis.dskTable
#view   systemview      excluded        enterprises.ucdavis.fileTable
#view   systemview      excluded        enterprises.ucdavis.laTable
#view   systemview      excluded        enterprises.ucdavis.logMatch
#view   systemview      excluded        enterprises.ucdavis.memory
#view   systemview      excluded        enterprises.ucdavis.prTable
#view   systemview      excluded        enterprises.ucdavis.snmperrs
#view   systemview      excluded        enterprises.ucdavis.systemStats
view    systemview      excluded        enterprises.ucdavis.ucdExperimental
#view   systemview      excluded        enterprises.ucdavis.version
# Present L7 MIB
view    systemview              included        .1.3.6.1.4.1.17304

Grant read-only access to the views for the groups:

#       group           context sec.model sec.level prefix read         write notif
access  monitors        ""      any       noauth    exact  systemview   none  none

syscontact Joe Administrator <jadministrator@mycompany.com>
syslocation Test system in lab

###############################################################################
# Process checks.
#
# Checks to see if processes called NAME are running on the agent
# machine. An error flag (1) and a description message are then
# passed to the 1.3.6.1.4.1.2021.2.1.100 and
# 1.3.6.1.4.1.2021.2.1.101 MIB columns (respectively) if the
# NAME’d program is not found in the process table as reported by
# "/bin/ps -e".
#
# If MAX and MIN are not specified, MAX is assumed to be infinity
# and MIN is assumed to be 1.
#
# If MAX is specified but MIN is not specified, MIN is assumed to
# be 0.
#
#  The following are examples of how to use the agent to check for
#  processes running on the host.  The syntax looks something like:
#
#  proc NAME [MAX=0] [MIN=0]
#
#  NAME:  the name of the process to check for.  It must match
#         exactly (ie, http will not find httpd processes).
#  MAX:   the maximum number allowed to be running.  Defaults to 0.
#  MIN:   the minimum number to be running.  Defaults to 0.
 
#  Make sure java is running
proc java
 
# make sure mysqld is running
proc mysqld
 
# make sure bogus is running (error condition test)
#proc bogus

###############################################################################
# disk checks
#
# Checks  the  named  disks  mounted  at  PATH for available disk
# space.  If the disk space is less than MINSPACE (kB) if  speci-
# fied  or  less than MINPERCENT (%) if a % sign is specified, or
# DEFDISKMINIMUMSPACE (kB) if not specified, the associated entry
# in  the  1.3.6.1.4.1.2021.9.1.100  MIB table will be set to (1)
# and a descriptive error message will be returned to queries  of
# 1.3.6.1.4.1.2021.9.1.101.
 
# The agent can check the amount of available disk space, and make
# sure it is above a set limit.
 
# disk PATH [MIN=100000]
#
# PATH:  mount path to the disk in question.
# MIN:   Disks with space below this value will have the Mib's errorFlag set.
#        Default value = 100000.
 
# Check the / partition and make sure it contains at least 10 gig
disk / 10485760

###############################################################################
# load average checks
#
# Checks the load average of the machine  and  returns  an  error
# flag  (1),  and  an  text-string  error  message  to queries of
# 1.3.6.1.4.1.2021.10.1.100     and     1.3.6.1.4.1.2021.10.1.101
# (respectively)  when the 1-minute, 5-minute, or 15-minute aver-
# ages exceed the associated maximum values.  If any of the MAX1,
# MAX5,  or MAX15 values are unspecified, they default to a value
# of DEFMAXLOADAVE.
 
# load [1MAX=12.0] [5MAX=12.0] [15MAX=12.0]
#
# 1MAX:   If the 1 minute load average is above this limit at query
#         time, the errorFlag will be set.
# 5MAX:   Similar, but for 5 min average.
# 15MAX:  Similar, but for 15 min average.
 
# Check for loads:
load 6 5 4

###############################################################################
# file size checks
#
# Monitors file sizes and makes sure they  don’t  grow  beyond  a
# certain  size  (in kilobytes).  MAXSIZE defaults to infinite if
# not specified, and only monitors  the  size  without  reporting
# errors about it.  A maximum of 20 files can be monitored.
 
# file FILE [MAXSIZE]
#
# FILE:    Full path to file
# MAXSIZE: Maximum file size (in kilobytes)
 
# ibdata starts at 1.0 GB. Set error if it exceeds 10.0 GB.
file /var/lib/mysql/ibdata 10485760
# Report on the default ssg log file
file /ssg/logs/default_-ssg_0_0.log
# Report on /var/log/messages
file /var/log/messages

The agent can invoke an external command or shell script to return the necessary information.
The agent can pass the request off to another (sub)agent, which already implements the required MIB.
You can write code to implement the new MIB objects, and include this within the agent by recompiling the agent.

#!/bin/sh
# CA Technologies, Inc
# This belongs in /ssg/bin
#
PATH=$PATH:/bin:/usr/bin
PLACE=".1.3.6.1.4.1.17304.7.1"
if [ "$1" = "-g" ]; then
    VERB="get";
elif [ "$1" = "-n" ]; then
    VERB="getnext";
elif [ "$1" = "-s" ]; then
    VERB="set";
fi
wget -q -O- http://127.0.0.1:8080/ssg/management/$VERB/$2
exit 0