What's the function of trap community?

[henrybb]

When I config snmp trap,I need config the community,in this example,it is "world".But my NMS doesn't config any about this community,and the NMS can receive the trap normally.

So why config the community ?

snmp-server host 10.1.20.28 world

thanks for your help

Henry

[rmushtaq]

You must specify the trap community string to be used when sending a trap. Like a community string with SNMP gets/sets, the trap community string is intended to provide a simple method to authenticate the source of the trap. Because the community string is sent over the network in clear text, it is not a very secure method for authentication. By default, most NMS trap reception software ignores the community string included with a trap. If this form of authentication is inadequate for your SNMP needs, consider using SNMP informs.