RAD Data comm IPmux-16 SNMP Communities , Authentication , Network Management Stations

Appendix B SNMP Management IPmux-16 Installation and Operation Manual
B-4 SNMP Environment
SNMP Communities
SNMP delimits management domains by defining communities. Each community
is identified by a name, which is an alphanumeric string of up to 255 characters
defined by the user.
The IPmux-16 SNMP agent defines strings of up to 10 characters (case sensitive,
numeric and alphabetical).
Any SNMP entity (both managed entities and management stations) is assigned a
community name by its user. In parallel, the user defines a list of the communities
for each SNMP entity that are authorized to communicate with the entity, and the
access rights associated with each community (this is the SNMP community name
table of the entity).
In general, SNMP agents support two types of access rights:
Read-Only: The SNMP agent accepts and processes only SNMP getRequest and
getNextRequest commands from management stations which have a Read-Only
community name.
Read-Write: The SNMP agent accepts and processes all the SNMP commands
received from a management station with a Read-Write community name.
Authentication
In accordance with SNMP protocol, the SNMP community of the originating entity
is sent in each message.
When an SNMP message is received by the addressed entity, it first checks the
originator's community. Messages with community names not included in the
SNMP community names table of the recipient are discarded. SNMP agents of
managed entities usually report this event by means of an authentication failure
trap.
The SNMP agents of managed entities evaluate messages originated by
communities appearing in the agent's SNMP community names table in
accordance with the access rights, as previously explained. Thus, a setRequest for
a MIB object with read-write access rights will nevertheless be rejected if it comes
from a management station whose community has read-only rights with respect to
that particular agent.
Network Management Stations
The IPmux-16 SNMP agent stores the IP address of the Network Management
Station (NMS) that is intended to manage it.