# WHATPORT(705)

## NAME

port 705 — AgentX — Where SNMP subagents plug their MIB subtrees into a master agent.

Protocol: TCP

## DESCRIPTION

AgentX (RFC 2741) splits an SNMP agent into a master agent that owns port 161 and subagents that register parts of the MIB tree with it; RFC 2741 assigns TCP 705 for that master/subagent link. Net-SNMP and similar stacks usually prefer a Unix domain socket (/var/agentx/master) and only fall back to TCP 705 when subagents live on another process boundary or host. The protocol has no authentication of its own — whatever connects can register or replace MIB subtrees on the master agent. On a scan it means a managed device or server with AgentX enabled over TCP.

## EXPOSURE

**Do not expose.** Unauthenticated by design and trusted to serve SNMP data; bind it to loopback or a Unix socket, never a routable interface.

## CHECK

```sh
sudo lsof -nP -iTCP:705 -sTCP:LISTEN
```

## SEE ALSO

- spec — [RFC 2741 — Agent Extensibility (AgentX) Protocol Version 1](https://www.rfc-editor.org/rfc/rfc2741.html) (rfc-editor.org)
- source — [Net-SNMP source repository](https://github.com/net-snmp/net-snmp) (github.com)

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