IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
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S 2.144 Selection of a suitable network management
protocol
Initiation responsibility: Head of IT Section, IT Security Management
Implementation responsibility: Administrators
The following standard protocols for network management are currently
applicable:
- SNMP (Simple Network Management Protocol); SNMP is described in
RFC 1157. Request for Comment (RFC) is a standard which has
established itself in the Internet.
- CMIP (Common Management Information Protocol); CMIP is described in
the ITU-T standard X.711 and in ISO/IEC 9596-1.
The main advantages and disadvantages of these two protocols are described
in the following in order to facilitate selection of the suitable network
management protocol when the need arises.
SNMP
Two components are defined for SNMP: a manager and an agent. In a local
network, one or more managers and one agent per IT system to be monitored
and configured via SNMP are installed. The agents gather information about
these systems and store this data in a MIB (management information base).
They exchange messages with the manager via a connectionless protocol, so
that SNMP does not rely on any particular transport protocol. Nowadays, it is
usually implemented on UDP/IP. However, other implementations are
possible and available (e.g. via OSI, AppleTalk, SPX/IPX). SNMP is available
in different versions. In addition to the original version SNMPv1, different
variants of version 2 (SNMPv2) are also in use to a limited extent (RFC 1901-
1908).
SNMP is an extremely simple protocol which recognises three types of
messages. Managers and agents use it to exchange what is known as
management information, which basically consists of the values of status
variables which are stored in management agents and describe the condition of
the related managed object. The management database (MIB) describes which
status variables (name and type) exist in each agent. The information is
organised hierarchically and each value is assigned a unique identification
number which defines a unique sequence of the variables. In detail, the types
of messages are:
1. GetRequest: sent from the manager to agents to query the values of one or
more status variables from them.
2. GetNextRequest: sent from the manager to agents to query the value or the
next values in accordance with the order of the variables in the MIB.
3. SetRequest: sent from the manager to agents in order to set the value of a
variable.
4. GetResponse: sent from agents to the manager in order to send the queried
values or confirm that the value of a variable has been set.
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IT-Baseline Protection Manual: Oktober 2000