SNMP - snmpd - some basic information

SNMP .. Simple Network Management Protocol

SNMP should be a simple asynchronous query/answer protocol, which is based on
a connectionless transport protocol (UDP).

SNMP reduces all network management functions to 4 operations:

o get reading is used to get specific management information
o set writing is used to change specific management information
o get-next an operation, which is used by a management station to check
all possible variables.
o trap is used to inform a management station about unexpected events

All objects, which should be managed are described in a Management Information
Base (MIB).
The MIB is divided into a public (MIB-II) and a private part (manufacturer
specific).

snmpd
-----

The snmpd is a daemon process, which realizes network management functions
as ordered be the manager.
When started, the snmpd learns all variables (MIB-II and private BinTec MIB)
of the ISDN communication software. Instructed by a management station,
the snmpd can change entries in the configuration files. Therefore you should
never change configuration files manually during the snmpd is active.
--------------------------------------------------------------------
Before the daemon is to be deactivated the snmpd superscribes the
configuration files with its own actual values.
So, if you want to change the configuration manually, you have to stop the
snmpd!

Starting and stopping the snmpd
-------------------------------

The handling of starting and stopping the snmpd differs from release to release,
one possibility is the script /etc/rc2.d/S99snmp, the other is the script
/usr/bianca/product/startup/280.snmp.

/etc/rc2.d/S99snmp
------------------
This file is consulted during the system boot, this is done normally in
releases < 4.2.1.2. To stop the daemon for manual changes in the configuration,
you can call "/etc/rc2.d/S99snmp stop" (/etc/rc2.d/S99snmp start for starting).

In releases >= 4.2.1.2 the snmpd is not started during system boot. There
you will find a file /etc/rc2.d/_S99snmp -> the file is not consulted, the
snmpd is not started.

/usr/bianca/product/startup/280.snmp -> 480.snmp
------------------------------------------------
In release 4.3.1.3 the snmpd is started with the script
/usr/bianca/bin/startup, which executes every file in the directory
/usr/bianca/product/startup.

In this release there is the following bug:
-------------------------------------------
Because of the prefix 280, the snmpd is started before ISI/BASE and ISI/IP.
This has the effect, that the snmpd knows nothing about the IP interfaces.
So, when snmpd reads the /usr/bianca/config/routes it superscribes all entries,
because it do not know any interface.

To correct this bug:
--------------------
!!! Move the file 280.snmp to 480.snmp. !!!
If you want to change the configuration, simply call /usr/bianca/bin/config or
call /usr/bianca/bin/bringdown and edit the configuration files manually.

System name
-----------
When snmpd is running, the system name is set by the variable sysname,
configured in the file /usr/isi/config/snmpd.conf. (To change the systemname:
stop the snmpd, edit the configuration file, start the snmpd).
If the snmpd is not used, the systemname is set during the system boot with
the script /etc/rc2.d/S11uname.

 

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