TCP経由のネットワークSNMP？

snmpgetもこれをサポートすると思います。一部の共通機能は snmpcmd(1M) のマニュアルページに記載されていますが、すべての個別のコマンドページでこれらの機能を繰り返すわけではありません。

 Agent Specification
     The agent specification (see SYNOPSIS) takes the form:

     [transport-specifier:]transport-address

     At its simplest, the agent specification consists of a host-
     name or an IPv4 address in the standard, "dotted quad" nota-
     tion. In this case, communication will  be  attempted  using
     UDP/IPv4  to  port  161  of  the  given host. Otherwise, the
     transport-address  part  of  the  specification  is   parsed
     according to the following table:

     <transport-specifier>   <transport-address> format

     udp                     hostname[:port]

     Note that transport-specifier strings  are  case-insensitive
     so  that,  for example, "tcp" and "TCP" are equivalent. Here
     are some examples, along with interpretations:

     myhost:161

     Perform query using UDP/IPv4 datagrams  sent  to  myhost  on
     port  161.  The  :161  is redundant here because that is the
     default SNMP port.

     udp:myhost

     Identical to the previous specification. The udp: is  redun-
     dant here because UDP/IPv4 is the default transport.