Where SNMP subagents plug their MIB subtrees into a master agent.
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.
Do not expose
Unauthenticated by design and trusted to serve SNMP data; bind it to loopback or a Unix socket, never a routable interface.
$ sudo lsof -nP -iTCP:705 -sTCP:LISTENSeen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
Get Beige Box →also available as JSON · Markdown
Corrections or a missing port? Reply @rimrocksystems.