HPUX ovsnmp.conf[4]
ovsnmp.conf(4) ovsnmp.conf(4)
NAME
ovsnmp.conf, ovsnmp.conf_db - OpenView SNMP Configuration Database
DESCRIPTION
The OpenView SNMP Configuration Database associates SNMP configuration
parameters with specified nodes in the managed environment. The
OpenView SNMP Library and all OpenView SNMP applications use the SNMP
Configuration Database to determine the parameters to use when issuing
SNMP requests to the managed nodes.
The configuration database also associates a status monitoring
interval with the specified nodes. This status monitoring
configuration is used by netmon to control how often it monitors
status of the nodes.
In release 3.3 of the OpenView SNMP Platform and Developer's Kit, the
ovsnmp.conf text file is replaced by an ndbm database ovsnmp.conf_db,
along with revised algorithms, to improve performance of SNMP
applications accessing the SNMP Configuration Database.
The ovsnmp.conf file is retained in release 3.3 as a read-only shadow
file for the SNMP Configuration Database to support SNMP applications
based on (i.e., linked with) the release 3.2 or prior SNMP Library.
The ovsnmp.conf file is automatically kept up-to-date with the SNMP
Configuration Database by the xnmsnmpconf configuration utility.
The default SNMP Configuration Database is stored in the
ovsnmp.conf_dbdirectory. The corresponding shadow file is ovsnmp.conf.
By convention, the name of the SNMP Configuration Database is derived
from the name of the corresponding shadow file by appending " _db" to
the shadow file name.
The SNMP configuration database is created with the following access
permissions. These permissions may be modified to fit site security
requirements.
ovsnmp.conf_db drwxrwxrwx
ovsnmp.conf_db/* rw-rw-rw-
ovsnmp.conf rw-rw-rw-
The xnmsnmpconf configuration utility provides both an X11/Motif
interactive interface and a command line non-interactive interface to
maintain the SNMP Configuration Database. Additionally, the SNMP
Configuration Database can be maintained by other applications using
the OVsnmpConf Application Programming Interface (API) included
Configuration Parameters
Three types of configuration entries are maintained in the SNMP
Configuration Database.
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Specific Target Node
A single managed node in the network. This node may be
accessed directly using the SNMP, or may only be accessible
using an SNMP proxy.
IP Address Wildcard
Identifies a group of IP addressable nodes using IP Address
ranges. The order of IP Address Wildcards has important
semantic meaning when determining the SNMP parameters for a
particular node during runtime operation (see Runtime
Operation for details).
Global Default
Default parameters for all other nodes.
Each entry in the SNMP Configuration Database consists of
the following parameters. The only mandatory field in each
entry is the Target. All other fields may be specified as
"use default value", in which case the actual parameter
value is determined during run-time operation (see Runtime
Operation for details).
Target The identity of the managed node to which SNMP requests are
directed. The target can be any of the following:
IP Hostname (i.e., site-gw.corp.com)
o IP Address (i.e., 128.1.3.1)
o IP Address Wildcard (i.e., 128.1-4.*.*)
o Non-SNMP Entity that is proxied (i.e.,
segment3)
An IP address wildcard has the form:
o <range>.<range>.<range>.<range>
where,
o <range> ::= <value> | <value>-<value> | *
o <value> ::= 0 .. 255
Proxy The identity of a proxy for the target node. When a proxy is
specified for the Target, SNMP requests issued by an
application to the target node are actually directed to the
proxy node on behalf of the target node.
If specified, the proxy must be either an IP Hostname or an
IP Address.
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Community The SNMP community name which the management application
uses as authorization when issuing SNMP Get and GetNext
requests to the Target.
This community name is also used for SNMP Set requests if
the management application cannot resolve an explicit Set
Community name for the Target.
The community name may consist of any character that you can
enter from the keyboard with the exception of ":". Blanks
are allowed but the total string length must be less than
256 characters.
Set Community
The SNMP community name which the management application
uses as authorization when issuing SNMP Set requests to the
Target.
Often times SNMP agents are configured with different
community names for Set requests than for Get requests. This
field enables you to configure the SNMP management
applications according to this distinction.
Timeout The amount of time, in tenths of a second, the management
application will initially wait for an SNMP response before
attempting to retry the SNMP request to the Target . The
timeout must be greater than or equal to zero. (If zero is
supplied, it will be silently rounded up to 1/10 second.)
See OVsnmpSend(3) for timeout algorithm details.
If SNMP requests to all agents are always timing out,
increase the default timeout value. If SNMP requests to a
specific agent is timing out, configure a larger timeout
value for that agent.
Retry Count
The maximum number of retries the management application
will attempt before concluding that the Target is
unreachable. The retry count must be greater than or equal
to zero. See OVsnmpSend(3)
for retry count algorithm details.
Remote Port
The UDP port number on the target or proxy node (as
appropriate) where the SNMP agent expects to receive SNMP
requests. The standard SNMP port is 161.
This field is generally used only for specialized proxy
agents which do not listen to the standard SNMP port.
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Status polling interval
The frequency, in seconds, at which netmon uses ping to
query the status of the target. This must be greater than
zero.
NOTE: The more frequently you poll for status, the more ping
traffic the manager and networks
Configuration Database Format
The internal structure of the SNMP Configuration Database is a
directory which contains two or three ndbm databases. Each of these
databases is composed of two files, a .dir and a .pag file. Hence
the directory which is the logical database should contain four or six
files.
Two ndbm databases should always be present. These two databases
contain the SNMP Configuration parameters describe above.
nodedb contains configuration parameters for specific managed
nodes. These entries are randomly accessed using the target
name.
wilddb contains configuration parameters for IP Address Wildcard
entries, and the Global Default configuration.
Since the IP Address Wildcard semantics are, in part,
determined by the order in which the wildcards are
specified, the wilddb is only accessed as a single list of
ordered entries. This is the same semantic meaning as in
prior releases.
A third ndbm database may also be present.
cachedb Contains fully resolved configuration parameters for nodes
previously referenced by runtime operations. The cachedb is
truncated to insure the accuracy of the cache entries
whenever the nodedb or the wilddb is modified.
The purpose of this database is to provide a cache which
persists across processes. This differs from the caching
used in prior releases, which cached on a per-process basis.
The significant advantage of the new caching technique is
that all processes gain the performance benefits of
previously determined SNMP parameters for SNMP requests made
by itself or any other process on the system.
The cachedb maintains the following parameters in addition
to those found in the nodedb.
o isProxied
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TRUE if proxied, FALSE otherwise
o ipAddrIP
Address of SNMP agent
o ipAddrAge
Time of last IP address name server lookup
The ipAddr and ipAddrAge are cached in order to minimize
dependence on the system IP address name server for name-
to-address mapping. The ipAddrAge is used to determine when
this mapping needs to be recomputed (see Runtime Operations
for details).
The xnmsnmpconf configuration utility includes command line options to
control the SNMP Configuration caching. Although caching is
recommended to improve performance of SNMP applications, IP Address
caching or both IP Address and SNMP Parameter caching may be disabled.
The IP Address Age Limit may also be configured using xnmsnmpconf.
Shadow (Compatibility) File Format
SNMP applications based on the Release 3.3 SNMP Library access
configuration parameters directly from the SNMP Configuration
Database. However, SNMP applications based on Release 3.2 or prior of
the SNMP Library have no such knowledge of the SNMP Configuration
Database. Therefore, the textual based ovsnmp.conf configuration file
of prior releases is maintained as a shadow file for the SNMP
Configuration Database. Whenever changes are made to the SNMP
Configuration Database using xnmsnmpconf, the ovsnmp.conf
configuration file is updated as well.
The format of the ovsnmp.conf configuration file is as follows:
o Blank lines are ignored.
o A " #" character indicates the beginning of a comment. All
characters from the " #" through the end of the line are
ignored.
o All other lines are considered configuration entries. Each
entry is specified on a separate line as seven colon separated
fields. Each colon separated field represents one of the
configuration parameters described above. The syntax is:
o target:community:proxy:timeout:retries:poll:port:set-community
o The target field is the only mandatory field. The same
conventions as described in Configuration Parameters specify
valid Specific Node and IP Address Wildcard targets. The
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Default Configuration is identified by "*.*.*.*" as the
target.
o An empty or missing field denotes use default. In this case,
the actual parameter used for the target is determined during
runtime operation.
o An asterisks (*) specified as the proxy field denotes do not
proxy. This is necessary to distinguish from use default proxy
which may be specified in a matching wildcard entry or the
global default entry.
Two additional fields, remote port and set community, are added to the
ovsnmp.conf configuration entry specification. However, the
The xnmsnmpconf configuration utility includes command line options to
control the content of the ovsnmp.conf shadow file. By default, all
entries in the SNMP Configuration Database are maintained in the
shadow file. However, you may disable shadow file maintenance if
there are no Release 3.2 or prior based applications installed on the
system. Alternatively, you may choose to only shadow those
configuration entries that are suitable for Release 3.2 or prior based
applications. Suitable entries are those which specify use default or
the standard SNMP port (161) in the remote portfield. The reason you
may
Run-time Operation
This section describes the behavior of SNMP applications with respect
to the SNMP Configuration Database. Specifically, the configuration
parameters and IP address of the target node must be determined as
part of SNMP session initialization.
If a cache entry does not exist for the specified target, or caching
is disabled, the following algorithm is used to resolve the
configuration parameters and the IP address for the target node.
o First, the Specific Node configurations are searched for an
entry that matches the target node. This search is done by
first using the node name specified by the application to
avoid an IP name server lookup for non-IP proxied nodes; then
by the full IP Domain Name if necessary. If a matching entry
is found, the parameters which are explicitly configured for
the node are resolved.
o Second, if an IP address for the target node name cannot be
determined using the IP name server, this step is skipped.
Otherwise, the IP Address Wildcard configurations are
searched. The order of IP Address Wildcard entries is
important when determining the SNMP parameters for the target
node. The wildcard list is sequentially searched for the
first entry which matches the IP address of the target node.
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If a matching entry is found, the parameters which are
explicitly configured for the wildcard entry and not yet
resolved for the node are resolved. The wildcard search
continues until all parameters for the node are resolved or no
other wildcard matches are found.
o Third, the Global Default values are applied to any remaining
parameters for the target node which have not yet been
resolved. If some unresolved parameters are not specified by
the Global Default configuration, hard-coded default values
are used. The hard-coded defaults are:
Community:
"public"
Set Community:
see Note
Proxy: none
Remote Port:
161
Retry Count:
3
Timeout: 0.8 seconds
Poll Interval:
5 minutes
Note: there is no pre-defined Set Community name. If Set Community is
not specified, the regular Community name configured for the target
node is used.
o Next, the IP Address of the SNMP agent is obtained using the
system IP name server if the address has not already been
determined. If the target is proxied for, this address is
the address of the proxy; otherwise the address is that of the
target node. If an IP address cannot be determined, an
unknown host error is returned to the application.
o If caching is enabled, a cache entry is created in the SNMP
Configuration Cache database.
Finally, the configuration parameters and IP address are
returned to the application for use in the SNMP session.
If caching is enable, and a cache entry already exists for the target
node name specified by the application, the parameters from the cache
entry are used with the following caveat:
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If the age of the cached IP address exceeds the IP Address Age
Limit, the IP address for the target or proxy node (as
appropriate) is obtained from the system IP name server. The
cache entry is then updated.
If there is a database error, such as a non-existent database or
invalid access permission to the database, the hard-coded default
configuration values are returned to the application.
By default, both IP Address and SNMP Parameter caching are enabled.
Use the xnmsnmpconf -optCache option to alter this behavior as
desired. Either IP Address only or both IP Address and SNMP Parameter
caching may be disabled.
The default IP Address Age Limit is 12 hours. Use the xnmsnmpconf
-optIpAgeLimit option to override this
To provide backward compatibility for applications which create and
reference a temporary ovsnmp.conf file identified by the
OVSNMP_CONF_FILE environment variable, the SNMP Library run-time
operation is designed to create a corresponding temporary database
containing entries from the ovsnmp.conffile. When the application
terminates, this temporary configuration database is automatically
removed, so the entire process is transparent to the application and
end-user.
EXAMPLES
Consider the following SNMP Configuration expressed in ovsnmp.conf
file format:
# target:community:proxy:timeout:retries:poll:port:set-
community
nodeA:passwd:*::4::::
15.6.80.6:secure:*:::30:::
segment1:monitor:rmon-probe:5:0:60::control:
coke_machine::15.6.80.11:30:::999:money:
15.6.80.1-5:oper:*::0:60::admin:
15.6.80.10-255:pass:*:25:1:120:::
15.6.*.*::*:20:2::::
*.*.*.*:public:*:8:3:300:161::
Using this configuration, SNMP requests will proceed as follows.
Assume the IP address of "nodeA" is 15.6.80.7, and the IP Address of
rmon-probe is 15.7.84.3.
Target Community SetComm T.out Retry Poll Port
Destination
------------ -------- ------- ----- ----- ---- ---- ---------
--
15.6.80.1 oper admin 8 0 60 161 15.6.80.1
15.6.80.6 secure secure 20 2 30 161 15.6.80.6
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nodeA passwd passwd 20 4 300 161 15.6.80.7
15.6.80.7 passwd passwd 20 4 300 161 15.6.80.7
15.6.80.10 pass pass 25 1 120 161 15.6.80.10
15.6.81.1 public public 20 2 300 161 15.6.81.1
coke_machine public money 30 3 300 999 15.6.80.11
segment1 monitor control 5 0 60 161 15.7.84.3
WARNINGS
Do not edit the ovsnmp.conf file directly without subsequently
importing the changes into the SNMP Configuration Database.
Applications based on the Release 3.2 or prior SNMP Library will
continue to experience degraded start-up performance as the number of
entries in the ovsnmp.conf file increases. Rebuilding the application
with the Release 3.3 SNMP Library will improve performance
significantly.
AUTHOR
ovsnmp.conf and ovsnmp.conf_db were developed by HP.
FILES
HP-UX 9.x and SunOS 4.1.x
/usr/OV/conf/snmp.conf
/usr/OV/conf/snmp.conf_db/*
HP-UX 10.x and Solaris 2.3, 2.4
/etc/opt/OV/share/conf/snmp.conf
/etc/opt/OV/share/conf/snmp.conf_db/*
Universal Pathname
$OV_CONF/snmp.conf
$OV_CONF/snmp.conf_db/*
Universal pathname paths are established according to your shell and
platform requirements. See the file that applies to your platform and
shell for more information about the script used to set HP OpenView
Network Node Manager environment variables:
HP-UX 9.x and SunOS 4.1.x
/usr/OV/bin/ov.envvars.sh (k shell)
/usr/OV/bin/ov.envvars.csh (c shell)
HP-UX 10.x and Solaris 2.3, 2.4
/opt/OV/bin/ov.envvars.sh (k shell)
/opt/OV/bin/ov.envvars.csh (c shell)
SEE ALSO
xnmsnmpconf(1)
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EXTERNAL INFLUENCES
Environment Variables
OVSNMP_CONF_FILE
The pathname specified by this variable overrides the default
configuration file and database names. The SNMP configuration database
name is derived from the environment variable setting by appending
"_db".
For example, setting OVSNMP_CONF_FILE equal to /conf/snmp_admin causes
xnmsnmpconf and the OpenView SNMP Library to use /conf/snmp_admin_db
as the SNMP Configuration database and /conf/snmp_admin as the shadow
file.
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