The Engine ID allows to uniquely identify the SNMP engines and entities apart from each other.

SNMP Engine IDs are composed of octets (not less than 5 octets and not more than 12) and there is no standard display format for them; they just need to be a hexadecimal string and they cannot be composed by all zeros or all 255s ("ff").

RFC 3411 specifies the architecture for SNMP management frameworks and it gives the following options of how the Engine can be formatted:

• IPv4 Address
• IPv6 Address
• MAC Address
• Text
• Octets

We suggest to use the format "Enterprise ID + Code + IPv4 Address":

For example:

Enterprise: 00:00:01 (it must start with 8)
Code: 1 (01)
IPv4 Address: 10.20.30.40 (0a:14:1e:28)

Engine ID: 80:00:01:01:0a:14:1e:28

In addition, since IWSVA uses Net-SNMP and there is a tmsnmpd.conf file that is modified via the WebUI, you can check some of its functions in the SNMPD.CONF document.

The following is an excerpt from the SNMPD.CONF document:

SNMPv3 Configuration

SNMPv3 requires an SNMP agent to define a unique "engine ID" in order to respond to SNMPv3 requests. This ID will normally be determined automatically, using two reasonably non-predictable values - a (pseudo-)random number and the current time in seconds. This is the recommended approach. However the capacity exists to define the engineID in other ways:

• engineID STRING

  Specifies that the engineID should be built from the given text STRING.

• engineIDType 1|2|3

  Specifies that the engineID should be built from the IPv4 address (1), IPv6 address (2) or MAC address (3). Note that changing the IP address (or switching the network interface card) may cause problems.

• engineIDNic INTERFACE

  Defines which interface to use when determining the MAC address. If engineIDType 3 is not specified, then this directive has no effect.
  The default is to use eth0.