<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Server can't receive the first packet if it is set to {active,false}. Change gen_udp:open param to {active,once}<div class=""><br class=""></div><div class="">Sergej<br class=""><div><blockquote type="cite" class=""><div class="">On 15 May 2017, at 11:27, yuzhu chen <<a href="mailto:billcyz@gmail.com" class="">billcyz@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">I've posted the same question on stackoverflow, but haven't got answers yet. So I posted this question again in here hoping for a solution.<div class=""><br class=""></div><div class=""><br class=""></div><div class=""><table style="margin:0px;padding:0px;border:0px;font-size:13px;border-collapse:collapse;color:rgb(36,39,41);font-family:arial,"helvetica neue",helvetica,sans-serif" class=""><tbody style="margin:0px;padding:0px;border:0px" class=""><tr style="margin:0px;padding:0px;border:0px" class=""><td class="gmail-votecell" style="padding:0px 15px 0px 0px;border:0px;vertical-align:top"><div class="gmail-vote" style="margin:0px;padding:0px;border:0px;text-align:center;min-width:46px"><span class="gmail-vote-count-post" style="margin:8px 0px;padding:0px;border:0px;font-size:20px;display:block;color:rgb(106,115,124)"><br class=""></span><a class="gmail-vote-down-off" title="This question does not show any research effort; it is unclear or not useful" style="margin:0px auto 10px;padding:0px;border:0px;font-size:1px;color:rgb(0,119,204);background-image:url("");background-size:initial;background-repeat:no-repeat;overflow:hidden;display:block;width:40px;height:30px;background-position:0px -220px">down vote</a><a class="gmail-star-off" href="http://stackoverflow.com/questions/43972714/erlang-udp-server-cant-receive-accept-packets#" title="Click to mark as favorite question (click again to undo)" style="margin:0px auto 2px;padding:0px;border:0px;font-size:1px;color:rgb(0,119,204);text-decoration:none;background-image:url("");background-size:initial;background-repeat:no-repeat;overflow:hidden;display:block;width:40px;height:30px;background-position:0px -120px">favorite</a><div class="gmail-favoritecount" style="margin:0px;padding:0px;border:0px"><span style="margin:0px;padding:0px;border:0px;color:rgb(106,115,124)" class=""></span></div></div></td><td class="gmail-postcell" style="padding:0px;border:0px;vertical-align:top"><div style="margin:0px;padding:0px;border:0px" class=""><div class="gmail-post-text" style="margin:0px 0px 5px;padding:0px;border:0px;font-size:15px;width:660px;word-wrap:break-word;line-height:1.3"><p style="margin:0px 0px 1em;padding:0px;border:0px;clear:both" class="">I have one simple udp server written in gen_server behaviour. When I run it, and try to send message by using gen_udp:send, the server replies nothing, seems like the udp server didn't accept packet successfully. Here is my code</p><p style="margin:0px 0px 1em;padding:0px;border:0px;clear:both" class="">gen_udp_server.erl:</p><pre class="gmail-prettyprint gmail-lang-erlang gmail-prettyprinted" style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-size:13px;width:auto;max-height:600px;overflow:auto;font-family:consolas,menlo,monaco,"lucida console","liberation mono","dejavu sans mono","bitstream vera sans mono","courier new",monospace,sans-serif;background-color:rgb(239,240,241);color:rgb(57,51,24);word-wrap:normal"><code style="margin:0px;padding:0px;border:0px;font-family:consolas,menlo,monaco,"lucida console","liberation mono","dejavu sans mono","bitstream vera sans mono","courier new",monospace,sans-serif;white-space:inherit" class=""><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-module</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">(gen_udp_server)</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
</span><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-behaviour</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">(gen_server)</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
</span><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-export</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">([init/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">1</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> handle_call/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">3</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> handle_cast/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">2</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> handle_info/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">2</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> terminate/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">2</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> code_change/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">3</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

</span><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-export</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">([start_link/</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">1</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

</span><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-define</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">SERVER</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">?MODULE).</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

</span><span class="gmail-kwd" style="margin:0px;padding:0px;border:0px;color:rgb(16,16,148)">-record</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">(state</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> {socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
                port</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
                local_ip</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
                broad_ip})</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

start_link(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Port</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">) ->
    {ok</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">} = gen_udp:open(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Port</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [binary</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> 
                                       {active</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> false}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
                                       {reuseaddr</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> true}])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
    gen_server:start_link(</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">?MODULE,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Port</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">]</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

init([</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Port</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">]) ->
    {ok</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> #state{socket = </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> port = </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Port</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

handle_cast(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Request</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">) ->
    {noreply</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

handle_call(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Request</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_From</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">) ->
    {noreply</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

handle_info({udp</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Addr</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Port</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Data</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> #state{socket = </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">} = </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">) ->
    inet:setopts(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [{active</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> once}])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
    io:format(</span><span class="gmail-str" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">"Server received data ~p from socket ~p~n"</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Data</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
    {ok</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

terminate(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Reason</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> {socket = </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">LSocket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}) ->
    gen_udp:close(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">LSocket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">)</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">

code_change(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_OldVsn</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">_Extra</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">) ->
    {ok</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">State</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span></code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;clear:both" class="">Starting server on server <a href="http://192.168.146.129/" class="">192.168.146.129</a>: <code style="margin:0px;padding:1px 5px;border:0px;font-size:13px;font-family:consolas,menlo,monaco,"lucida console","liberation mono","dejavu sans mono","bitstream vera sans mono","courier new",monospace,sans-serif;background-color:rgb(239,240,241);white-space:pre-wrap" class="">gen_udp_server:start_link(10000).</code></p><p style="margin:0px 0px 1em;padding:0px;border:0px;clear:both" class="">Sending message from <a href="http://192.168.146.128/" class="">192.168.146.128</a>:</p><pre class="gmail-prettyprint gmail-lang-erlang gmail-prettyprinted" style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-size:13px;width:auto;max-height:600px;overflow:auto;font-family:consolas,menlo,monaco,"lucida console","liberation mono","dejavu sans mono","bitstream vera sans mono","courier new",monospace,sans-serif;background-color:rgb(239,240,241);color:rgb(57,51,24);word-wrap:normal"><code style="margin:0px;padding:0px;border:0px;font-family:consolas,menlo,monaco,"lucida console","liberation mono","dejavu sans mono","bitstream vera sans mono","courier new",monospace,sans-serif;white-space:inherit" class=""><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">{ok</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">} = gen_udp:open(</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">4399</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> [binary</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> {active</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> false}])</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">
gen_udp:send(</span><span class="gmail-typ" style="margin:0px;padding:0px;border:0px;color:rgb(43,145,175)">Socket</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> {</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">192</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">168</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">146</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">129</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">}</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-lit" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">10000</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">,</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)"> </span><span class="gmail-str" style="margin:0px;padding:0px;border:0px;color:rgb(125,39,39)">"hello"</span><span class="gmail-pln" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">)</span><span class="gmail-pun" style="margin:0px;padding:0px;border:0px;color:rgb(48,51,54)">.</span></code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;clear:both" class="">The udp server should print some message when it receives packets, but my one failed. Can anyone help me?</p></div></div></td></tr></tbody></table></div></div>
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