anchor.diff:                     ok = api_to_connect_tcp(InitState)
              end).
   
  +api_to_connect_cond() ->
  +    api_to_connect_cond(os:type(), os:version()).
  +
  +%% I don't know exactly at which version this starts to work.
  +%% I know it does not work for 4.4.*, but is does for 4.15.
  +%% So, just to simplify, we require atleast 4.15
  +api_to_connect_cond({unix, linux}, {Maj, Min, _Rev}) ->
  +    if
  +        ((Maj >= 4) andalso (Min >= 15)) ->
  +            ok;
  +        true ->
  +            skip("TC does not work")
  +    end;
  +%% Only test on one machine, which has version 6.3, and there it does
  +%% not work, so disable for all.
  +api_to_connect_cond({unix, openbsd}, _) ->
  +    skip("TC does not work");
  +api_to_connect_cond({unix, freebsd}, {Maj, Min, _Rev}) ->
  +    if
  +        ((Maj >= 10) andalso (Min >= 4)) ->
  +            ok;
  +        true ->
  +            skip("TC may not work")
  +    end;
  +api_to_connect_cond({unix, sunos}, {Maj, Min, _Rev}) ->
  +    if
  +        ((Maj >= 5) andalso (Min >= 10)) ->
  +            ok;
  +        true ->
  +            skip("TC may not work")
  +    end;
  +api_to_connect_cond(_, _) ->
  +    skip("TC may not work").
  +
  +
   
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
  
positive.code:     Msg = l2b(?TPP_SMALL),
      Num = ?TPP_SMALL_NUM,
      tc_try(traffic_ping_pong_small_sendmsg_and_recvmsg_udp6,
             fun() ->
                     not_yet_implemented(),
                     ?TT(?SECS(20)),
                     InitState = #{domain => inet,
                                   msg    => Msg,
  
negative.code:     Msg = l2b(?TPP_MEDIUM),
      Num = ?TPP_MEDIUM_NUM,
      tc_try(traffic_ping_pong_medium_send_and_recv_tcp6,
             fun() -> has_support_ipv6() end,
             fun() ->
                     ?TT(?SECS(30)),
                     InitState = #{domain => inet6,
                                   msg    => Msg,
  