Port 705 is also known as AgentX or Agent eXtensibility. The agent is part of protocols that are used as part of querying applications. Other agents in this category are SMUX and proxied SNMP. The three operate together and one operates as master while delegating roles to the rest. The agent to which roles are delegated is known as a subagent. In their operations, proxy SNMP and SMUX generally make use of the SNMP format, but with one main difference – the SNMP when employed as a subagent is not aware that it is serving in that role. Operating on a non-standard port, SNMP normally listens on the port and receives requests from the master agent, which it then forwards in a standard format. For SNMP, which is acting as a subagent, the requests seem to be originating from a local host.
The set up for SMUX is almost similar although in the latter case a password is provided by the agent who will have registered with the master agent. Although AgentX has superseded SMUX, the latter still does work in order to facilitate SMUX subagents still in operation. The SMUX subagent could act as a master agent with the Net-SNMP agent but this suite does not provide for the existence of a subagent API. The use of SMUX in any case has dwindled substantially because of the little knowledge about its use among software developers. Moreover, support for SMUX has to be configured by following appropriate applications as it is not configured automatically for port 705. The result has been that when help is needed on the operation of SMUX, not much is available.