You can assign groups of hosts to simple network management protocol (SNMP) communities for limited security checking of agents and management systems or for administrative purposes. Communities are identified by community names that you assign. A host can belong to multiple communities at the same time, but an agent does not accept a request from a management system outside its list of acceptable community names.
See Best practices
Define communities logically to take advantage of the basic authentication service provided by SNMP. In the following example, there are two communities: Public 1 and Public 2.
Agent 1 can send traps and other messages to Manager 2 because they are both members of the Public 2 community.
Agents 2-4 can send traps and messages to Manager 1 because they are all members, by default, of the Public 1 community.
Community names are managed by configuring SNMP security properties.
There is no relationship between community names and domain or workgroup names. Community names represent a shared password for groups of network hosts, and should be selected and changed as you would change any password.