SNMPD(1M) UNIX 5.0 (14 Sep 1989) SNMPD(1M)
NAME
snmpd - minimal SNMP agent for BSD UNIX
SYNOPSIS
snmpd [-d] [-t] [-x] [-z] [-p portno] [-a x121address]
[-i pid] [-r]
(under /usr/etc/inet/snmpd)
DESCRIPTION
The snmpd server acts as a management agent, implementing
the Simple Network Management Protocol for Berkeley UNIX
systems. Upon receipt of a message, it authenticates the
request, attempts the operation, and then returns a
response.
The managed objects manipulated by snmpd are defined in the
file snmpd.defs, kept in the system administrator's area.
These objects conform to the Internet-standard Management
Information Base (commonly referred to as MIB-I), which is
defined in RFC 1066. The rules used for naming and
describing objects are taken from the Internet-standard
Structure of Management Information (SMI), which is defined
in RFC 1065.
At present, snmpd permits only a read-only SNMP access mode.
This restriction may be lifted in the future.
Most objects are realized via reading /dev/kmem. There are
some exceptions, which can be set via a configuration file,
which is read once, when the daemon starts.
TRANSPORTS
For a UDP-based network service, the server listens on port
161 for SNMP messages. The `-p' option overrides the
default UDP port.
For an X.25-based network service, the server implements the
transport class 0 protocol, decodes the connection request
packet, and execs the appropriate program to enter the
protocol and provide the service. The `-a' switch is used
to specify the X.121 address of the local host - this
overrides the entry in the isotailor file. In addition, the
`-i' switch is used to specify the protocol ID to listen on
- the default is 03018200. Note that on most X.25
implementations, if the local X.121 address is not present
in the isotailor file, then the `-a' switch must be used in
order for the server to receive incoming calls.
For a TP4-based transport service, the server simply listens
to any incoming connections for selector snmp.
By default, all network services are enabled (if defined in
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the configuration). The `-t' option specifies TCP-only
operation, the `-x' option specifies X.25-only operation,
and the `-z' option specifies TP4-only operation.
CONFIGURATION
The snmpd.rc file, which is kept in the system
administrator's area, contains customization commands. This
file must be owned by root unless the `-r' option is given.
At present, the directives are:
community name address access
defines an SNMP community called `name'. The `address'
token is either a hostname, an IP-address, or a network
address (using Kille's string syntax). If a value
other than 0.0.0.0 is used, then incoming messages
claiming to belong to the named community must come
from this address. The `access' token is either
readOnly or readWrite.
logging ava ...
sets the logging parameters accordingly. The one or
more `ava' tokens are of the form attribute=value. The
attributes are: file, which is the filename for the
log, this is interpreted relative to the ISODE logging
area, unless the value starts with a slash; size, which
takes an integer value describing the maximum file size
(in KBytes) that the log should be allowed to grow;
slevel, which takes a string value indicating which
events should be logged (one of none, fatal,
exceptions, notice, trace, pdus, debug, or all);
dlevel, which says which events should not be logged;
sflags, which takes a string value indicating logging
options should be enabled (one of close (to close the
log after each entry), create (to create the log if it
does not already exist), zero (to reset the log if the
size is exceeded), and tty (to log events to the user's
terminal in addition to the file)); and, dflags, which
says which logging options should be disabled.
trap name address
defines a trap sink for the SNMP community called
`name', on the indicated address, which is either a
hostname, an IP-address, or a network address (using
Kille's string syntax). Note that at present, traps
sinks must be reachable via UDP (the network address
must be an IP-address).
variable name value
sets the named variable to the indicated value. At
present, these variables may be set: sysDescr, which
takes a string value describing the management agent;
sysObjectID, which takes an OBJECT IDENTIFIER value
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containing similar information; sysLocation, which
takes a string value describing the location of the
agent; and, sysServices, which takes an integer
describing the services offered by the agent. See RFC
1066 for a more thorough explanation of these objects.
(The last two are defined in the new draft for MIB-II,
the follow-on to RFC 1066.)
variable snmpEnableAuthTraps [ enabled | disabled ]
enables (or disables) the generation of
authenticationFailure traps.
variable interface name ava ...
sets attributes for the named interface. The `name'
token is an interface name as reported by netstat -i.
The one or more `ava' tokens are of the form
attribute=value. At present, only three attributes may
be set for each interface: ifType, which takes an
integer value describing the kind of interface;
ifSpeed, which takes an integer value describing the
speed of the interface; and, ifAdminStatus, which takes
an integer value describing the adminstrative state of
the interface. See RFC 1066 for a more thorough
explanation of these objects.
DEBUG OPERATION
If snmpd is started interactively, or if the `-d' switch is
given, then debug mode is entered. In this case, all
logging activity is displayed on the user's terminal. In
addition, the logging information is more verbose.
FILES
snmpd.defs MIB definitions
snmpd.rc configuration file
snmpd.log log file
/etc/snmpd.piddaemon PID file
NOTE WELL
The names of the objects in snmpd.defs are case sensitive.
This was necessary to improve the efficiency of the hashing
algorithm used for object lookup.
SEE ALSO
RFCs 1065, 1066, and 1098.
S.E. Kille, A string encoding of Presentation Address,
Research Note RN/89/14, Department of Computer Science,
University College London, (February, 1989).
AUTHOR
Marshall T. Rose, NYSERNet Inc. This work was partially
supported by the U.S. Defense Advanced Research Projects
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Agency and the Rome Air Development Center of the U.S. Air
Force Systems Command under contract number F30602-88-C-
0016.
Although this package is distributed with the ISODE, it is
not an OSI program, per se. Inasmuch as the continued
survival of the Internet hinges on all nodes becoming
network manageable, this package was developed using the
ISODE and is being freely distributed with releases of
Berkeley UNIX.
It must be stressed that this package is not a complete
network management system. In particular, whilst snmpd
provides a minimal agent functionality, there are no Network
Operation Center (NOC) tools--snmpi is a debugging aid only.
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