MFC r345843:

MFC r345843:
  Follow the declared behaviour that specifies server string format in
  bsnmpclient(3).

  snmp_parse_server() function accepts string where some fields can be
  omitted: [trans::][community@][server][:port]

  "trans" field can be "udp", "udp6", "dgram" and "stream".
  "community" can be empty string, if it is omitted, the default value
  will be used. For read_community it is "public", for write_comminity
  it is "private". "server" field can be hostname, IPv4 address or IPv6
  address. IPv6 address should be specified in brackets "[]".
  If port is omitted, the default value "snmp" will be used for "udp"
  and "udp6" transports. So, now for bsnmpget(1) and bsnmwalk(1) it is
  not required to specify all fields in argument of '-s' option. E.g.

    # bsnmpget -s 127.1 sysName.0
    # bsnmpget -s "udp::127.1" sysName.0
    # bsnmpget -s "udp::public@127.1" sysName.0
    # bsnmpget -s "udp::public@127.1:161" sysName.0
    # bsnmpget -s "udp::[::1]" sysName.0
    # bsnmpget -s "udp6::[::1]" sysName.0
    # bsnmpget -s "[fe80::1%lo0]" sysName.0

  PR:		236664
  Reported by:	olivier