Name

snmpd.conf − Simple Network Management Protocol (SNMP) daemon configuration file

Description

The /etc/snmpd.conf file is a configuration file that contains information used by the snmpd daemon to define the static variables whose values are not available in the kernel.  It is created for you when you run the snmpsetup command, or you can create it manually. The system or network manager is usually responsible for maintaining it.

The following are the /etc/snmpd.conf file variables and their significance:

sysDescr ID-string
The sysDescr variable describes the host. The ID-string is the value of the variable mgmt.mib.system.sysDescr. The default sysDescr entry is of the form:

hostname:machine-type:software id

For example, the sysDescr entry for a MicroVAX II named host1 that is running ULTRIX Version 4.0 might read:

sysDescrhost1:MicroVAXII:ULTRIX V4.0 (Rev 64) System #2

interface speed name speed
The interface speed variable describes a value for the Management Information Base (MIB) variable defined as:

mgmt.mib.interfaces.ifTable.ifEntry.ifSpeed

The name parameter must be an ULTRIX interface name, such as sl0.  The following interfaces have default interface speeds and types: de, qe, ni, ln, se, scs, xna.  If your system has one of these interfaces, you do not need to specify this parameter. 

The speed parameter is a decimal number that describes the speed of the link in bits per second.  If you do not specify the speed parameter, snmpd does not return this variable and marks it as unavailable.

interface type name type
The interface type variable describes a value for the MIB variable in the interface table defined as:

mgmt.mib.interfaces.ifTable.ifEntry.ifType

The name parameter must be an ULTRIX interface name, such as sl0. 

See the sample /etc/snmpd.conf file in the Examples section for a complete listing of the possible type specifications.  If the type parameter is not specified, snmpd marks it as unavailable.

tcpRtoAlgorithm algorithm-type
The tcpRtoAlgorithm variable describes a value for the MIB variable in the tcp group defined as mgmt.mib.tcp.tcpRtoAlgorithm. This variable defines the Retransmission Time-Out (RTO) algorithm your system uses.

The algorithm-type parameter is a numeric code that represents the type of RTO algorithm you are using.  The default algorithm is Van Jacobson’s, which is algorithm number 4.  See the sample snmpd.conf file in the Examples section for a listing of the other algorithms.

If you do not specify this parameter, snmpd does not return this variable, and marks it as unavailable.

community name IP-address type
The community variable describes an SNMP community for the agent.

The name parameter is a string that describes the name of the community. 

The IP-address parameter is the dot-notation Internet Protocol (IP) address for the server.  Only SNMP packets coming from that address are accepted.  If you specify 0.0.0.0 in the address field, the SNMP agent honors the request from any Network Management Station (NMS) having the name community. 

The type parameter can be one of the following:

read-only
Permits only monitoring of variables.

read-write
Permits both monitoring and setting of variables.

traps
Generates traps when appropriate and sends them to the specified address with the specified community name.

The possible traps currently generated are cold start and authentication failure. 

If you do not specify any community, snmpd uses the default community public with an address 0.0.0.0 and a read-only type. Invalid uses of communities are logged with the syslog command.  To limit the use of a community to a finite group of machines, specify another community clause with the same community parameter name and a different address. 

timeout value
The timeout variable indicates the timeout value in seconds between the Agent and the Extended Agent.  If the Agent does not receive a response within the allotted time, it returns an error message to the NMS.  The default timeout value is 5 seconds.

extension extended-agent p1 p2 p3 p4
The extension variable lists the pathname of the extended-agent that the Agent activates. 

Variables p1 through p4 are passed by the Agent to the Extended Agent; p1 is usually the process name to be given to the Extended Agent. 

Examples

The default snmpd.conf file contains only the following entry:

community public 0.0.0.0    read-only

The following is an example of an extensive snmpd.conf file:

#
#    snmpd.conf file
#
sysDescr        host1:MicroVAXII:ULTRIX V4.0 System #2
  #
#  Describe the TCP RTO algorithm you are using.  Values
#  are listed in RFC 1066, under the TCP group variable:
#  tcpRtoAlgorithm
#  They are:
#
#  other    (1)  -- None of the below
#  constant (2)  -- constant RTO
#  rsre     (3)  -- MILSTD 1778, appendix B
#  vanj     (4)  -- Van Jacobson’s algorithm
#
tcprtoalgorithm4
 #
#  Describe who can use your SNMP daemon by
#  defining "communities".    USAGE:
#
#  community <name><IP address><type>
#
#  This is a limited-use community; a finite number of
#  hosts can use it.
#  Can only query from this community.
#
community test1128.45.10.100 read-only
community test1128.45.10.101 read-only
 #
#  These are our wide-open, general-use communities.  Specifying
#  0.0.0.0 means that any address can use this community only
#  to monitor variables.
#
community public 0.0.0.0 read-only
 #
#  This is our only management community.  You can set variables
#  as well as monitor variables with this community.  It is a
#  wide-open community as well.
#
community testwrite 0.0.0.0 read-write
 #
#  This is a trap community.  We send traps to these addresses
#  all from the same community name.  Note that a 0.0.0.0
#  address in a trap session is illegal and snmpd will ignore
#  that community definition.
#
community trap1128.45.10.100 traps
community trap1128.45.10.101 traps
 #
#  The interface speed is given in bits/sec.  USAGE:
#
#  interface speed <name> <speed>
#
interface speed sl0 9600
 #
#  The <name> parameter for the interface type is the
#  same as the <name> for the interface speed, sl0 for
#  this example.  USAGE:
#
#  interface type <name> <type>
#
#  The code number for the proper interface hardware type
#  is specified in RFC 1066 under the ifType object
#  definition.
#
#  Some possible values:
#
#  other                   (1)
#  regular1822             (2)
#  hdh1822                 (3)
#  ddn-x25                 (4)
#  rfc877-x25              (5)
#  ethernet-csmacd         (6)
#  iso88023-csmacd         (7)
#  iso88024-tokenBus       (8)
#  iso88025-tokenRing      (9)
#  iso88026-man            (10)
#  starLan                 (11)
#  Proteon-10MBit          (12)
#  Proteon-80MBit          (13)
#  hyperchannel            (14)
#  fddi                    (15)
#  lapb                    (16)
#  sdlc                    (17)
#  t1-carrier              (18)
#  cept                    (19) -- European equivalent of T-1
#  basicIsdn               (20)
#  primaryIsdn             (21)
#  propPointToPointSerial  (22) -- proprietary serial
#
interface type  sl0 1
 #
# Timer value to time out requests to extended agents.
#
timeout6
 #
# List of extended agents.
#
extension /etc/snmpextdsnmpextd

In this example, note the following:

•  Community test1 can be monitored by either 128.45.10.100 or 128.45.10.101.

•  Community public can be monitored by any NMS.

•  Community testwrite can be monitored and managed by any NMS.

•  When a trap is generated, it is sent to community trap1 at 128.45.10.100 or 128.45.10.101.  Destination addresses must have a mechanism in place to handle the traps.

See Also

snmpext(3n), snmpd(8n), snmpsetup(8n)
RFC 1066—Management Information Base for Network Management of TCP/IP- based Internets
RFC 1067—A Simple Network Management Protocol
Guide to Networking