Free Windows Help Tutorials sponsored by inkjet printer cartridges dot org /title> <META HTTP-EQUIV="imagetoolbar" CONTENT="no"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=ISO 8859-1"> <META name="description" Content="Hundreds of downloadable Windows help tutorials, articles and how-to guides sponsored by inkjet printer cartridges dot org."><style type="text/css">  </style> </head> <body bgcolor=#999999 vlink=blue link=blue> <span name = "INTRA" class="pg" style="top:0px; left:5px; width:714px; height:1010px"></span> <span name = "INTRA" style='top:0px; left:5px; height:1010px; width:714px' class='img'> <img src="pg0002im.png" height = "1010 width = "714" border="0"> </span> <span class='nav' style='left: 10px; top: 10px'><pre></pre></span><span name = "INTRA" style='top:51px; left:48px' class="ft3"><pre><font face='Helvetica'>Connectivity:Overview</font></pre></span> <span name = "INTRA" style='top:203px; left:91px' class="ft0"><pre><font face='Arial'>It is valid for the return path to be</font></pre></span> <span name = "INTRA" style='top:215px; left:77px' class="ft0"><pre><font face='Arial'>null, as in MAIL FROM: <> . This is</font></pre></span> <span name = "INTRA" style='top:227px; left:77px' class="ft0"><pre><font face='Arial'>typically used when sending an error</font></pre></span> <span name = "INTRA" style='top:218px; left:285px' class="ft2"><pre><font face='Arial'><i> The</i> <i>return</i> <i>path</i> <i>is</i> <i>the</i> <i>address</i> <i>that</i> <i>any</i></font></pre></span> <span name = "INTRA" style='top:239px; left:77px' class="ft0"><pre><font face='Arial'>report. A null return path means that</font></pre></span> <span name = "INTRA" style='top:251px; left:77px' class="ft0"><pre><font face='Arial'>no delivery failure report is required.</font></pre></span> <span name = "INTRA" style='top:242px; left:282px' class="ft2"><pre><font face='Arial'><i>error</i> <i>report</i> <i> </i> <i>such</i> <i>as</i> <i>would</i> <i>be</i> <i>generated</i></font></pre></span> <span name = "INTRA" style='top:263px; left:77px' class="ft0"><pre><font face='Arial'>Its main purpose is to avoid getting</font></pre></span> <span name = "INTRA" style='top:275px; left:77px' class="ft0"><pre><font face='Arial'>into the situation in which delivery fail </font></pre></span> <span name = "INTRA" style='top:266px; left:273px' class="ft2"><pre><font face='Arial'><i>if</i> <i>the</i> <i>message</i> <i>is</i> <i>undeliverable</i> <i> </i> <i>is</i> <i>sent</i> <i>to. </i></font></pre></span> <span name = "INTRA" style='top:287px; left:77px' class="ft0"><pre><font face='Arial'>ure messages continually shuttle back</font></pre></span> <span name = "INTRA" style='top:299px; left:77px' class="ft0"><pre><font face='Arial'>and forth because both sender and re </font></pre></span> <span name = "INTRA" style='top:311px; left:77px' class="ft0"><pre><font face='Arial'>cipient addresses are unreachable.</font></pre></span> <span name = "INTRA" style='top:323px; left:91px' class="ft0"><pre><font face='Arial'>The recipients of a message are de </font></pre></span> <span name = "INTRA" style='top:324px; left:272px' class="ft0"><pre><font face='Arial'>will not appear in the headers at all.</font></pre></span> <span name = "INTRA" style='top:324px; left:466px' class="ft0"><pre><font face='Arial'>lookup on it. However, a mail server</font></pre></span> <span name = "INTRA" style='top:335px; left:77px' class="ft0"><pre><font face='Arial'>fined using the command RCPT TO:</font></pre></span> <span name = "INTRA" style='top:336px; left:286px' class="ft0"><pre><font face='Arial'>Each recipient is acknowledged</font></pre></span> <span name = "INTRA" style='top:336px; left:466px' class="ft0"><pre><font face='Arial'>intended to receive messages for local</font></pre></span> <span name = "INTRA" style='top:347px; left:77px' class="ft0"><pre><font face='Arial'><address> . Each address is enclosed</font></pre></span> <span name = "INTRA" style='top:348px; left:272px' class="ft0"><pre><font face='Arial'>with a 250 OK reply. A recipient may</font></pre></span> <span name = "INTRA" style='top:348px; left:466px' class="ft0"><pre><font face='Arial'>users only would reject recipients that</font></pre></span> <span name = "INTRA" style='top:359px; left:77px' class="ft0"><pre><font face='Arial'>in angle brackets. A message may have</font></pre></span> <span name = "INTRA" style='top:360px; left:272px' class="ft0"><pre><font face='Arial'>also be rejected using a reply with a 550</font></pre></span> <span name = "INTRA" style='top:360px; left:466px' class="ft0"><pre><font face='Arial'>aren't at that domain.</font></pre></span> <span name = "INTRA" style='top:371px; left:77px' class="ft0"><pre><font face='Arial'>many recipients, and an RCPT TO:</font></pre></span> <span name = "INTRA" style='top:372px; left:272px' class="ft0"><pre><font face='Arial'>reply code. This depends on how the</font></pre></span> <span name = "INTRA" style='top:372px; left:480px' class="ft0"><pre><font face='Arial'>Other replies may be received in</font></pre></span> <span name = "INTRA" style='top:383px; left:77px' class="ft0"><pre><font face='Arial'>command is sent for each one. It is the</font></pre></span> <span name = "INTRA" style='top:384px; left:272px' class="ft0"><pre><font face='Arial'>server has been configured. Dial up</font></pre></span> <span name = "INTRA" style='top:384px; left:466px' class="ft0"><pre><font face='Arial'>response to RCPT TO: messages as a</font></pre></span> <span name = "INTRA" style='top:395px; left:77px' class="ft0"><pre><font face='Arial'>RCPT TO: command, not anything in</font></pre></span> <span name = "INTRA" style='top:396px; left:272px' class="ft0"><pre><font face='Arial'>ISP SMTP relay servers may accept</font></pre></span> <span name = "INTRA" style='top:396px; left:466px' class="ft0"><pre><font face='Arial'>result of the SMTP server being help </font></pre></span> <span name = "INTRA" style='top:408px; left:77px' class="ft0"><pre><font face='Arial'>the message headers, that results in a</font></pre></span> <span name = "INTRA" style='top:408px; left:272px' class="ft0"><pre><font face='Arial'>every RCPT TO: command, even if the</font></pre></span> <span name = "INTRA" style='top:408px; left:466px' class="ft0"><pre><font face='Arial'>ful. If an address is incorrect but the</font></pre></span> <span name = "INTRA" style='top:420px; left:77px' class="ft0"><pre><font face='Arial'>message arriving at its destination. In</font></pre></span> <span name = "INTRA" style='top:420px; left:272px' class="ft0"><pre><font face='Arial'>address specified is invalid, because</font></pre></span> <span name = "INTRA" style='top:420px; left:466px' class="ft0"><pre><font face='Arial'>server knows the correct address it</font></pre></span> <span name = "INTRA" style='top:432px; left:77px' class="ft0"><pre><font face='Arial'>the case of blind carbon copies or list</font></pre></span> <span name = "INTRA" style='top:432px; left:272px' class="ft0"><pre><font face='Arial'>the server doesn't know that the ad </font></pre></span> <span name = "INTRA" style='top:432px; left:466px' class="ft0"><pre><font face='Arial'>could respond with 251 User not lo </font></pre></span> <span name = "INTRA" style='top:444px; left:77px' class="ft0"><pre><font face='Arial'>server messages the recipient address</font></pre></span> <span name = "INTRA" style='top:444px; left:272px' class="ft0"><pre><font face='Arial'>dress is invalid until it does a DNS</font></pre></span> <span name = "INTRA" style='top:444px; left:466px' class="ft0"><pre><font face='Arial'>cal; will forward to <address> or 551</font></pre></span> <span name = "INTRA" style='top:456px; left:466px' class="ft0"><pre><font face='Arial'>User not local; please try <address> .</font></pre></span> <span name = "INTRA" style='top:468px; left:466px' class="ft0"><pre><font face='Arial'>Note the different reply codes signify </font></pre></span> <span name = "INTRA" style='top:480px; left:155px' class="ft1"><pre><font face='Arial'><i><b>Application</b></i> <i><b>Protocol</b></i> <i><b>Reply</b></i> <i><b>Codes</b></i></font></pre></span> <span name = "INTRA" style='top:480px; left:466px' class="ft0"><pre><font face='Arial'>ing whether the server has routed the</font></pre></span> <span name = "INTRA" style='top:492px; left:466px' class="ft0"><pre><font face='Arial'>message or not. These replies aren't</font></pre></span> <span name = "INTRA" style='top:502px; left:88px' class="ft0"><pre><font face='Arial'>Many Internet application layer protocols which are based on ASCII text</font></pre></span> <span name = "INTRA" style='top:504px; left:466px' class="ft0"><pre><font face='Arial'>common, and a mail client may simply</font></pre></span> <span name = "INTRA" style='top:514px; left:88px' class="ft0"><pre><font face='Arial'>commands use a system of replies in which an initial three digit code</font></pre></span> <span name = "INTRA" style='top:516px; left:466px' class="ft0"><pre><font face='Arial'>treat the 551 response as an error,</font></pre></span> <span name = "INTRA" style='top:526px; left:88px' class="ft0"><pre><font face='Arial'>provides the essential status information. Each digit has a particular mean </font></pre></span> <span name = "INTRA" style='top:528px; left:466px' class="ft0"><pre><font face='Arial'>rather than try to parse the alternative</font></pre></span> <span name = "INTRA" style='top:538px; left:88px' class="ft0"><pre><font face='Arial'>ing, as shown below.</font></pre></span> <span name = "INTRA" style='top:540px; left:466px' class="ft0"><pre><font face='Arial'>address out of the reply text.</font></pre></span> <span name = "INTRA" style='top:552px; left:480px' class="ft0"><pre><font face='Arial'>For the sake of completeness it</font></pre></span> <span name = "INTRA" style='top:558px; left:88px' class="ft0"><pre><font face='Arial'>First Digit</font></pre></span> <span name = "INTRA" style='top:564px; left:466px' class="ft0"><pre><font face='Arial'>should be pointed out that RCPT TO:</font></pre></span> <span name = "INTRA" style='top:574px; left:88px' class="ft0"><pre><font face='Arial'>1xx: Positive Preliminary Reply. Command accepted but held awaiting a</font></pre></span> <span name = "INTRA" style='top:577px; left:466px' class="ft0"><pre><font face='Arial'>commands may specify routes, not</font></pre></span> <span name = "INTRA" style='top:586px; left:88px' class="ft0"><pre><font face='Arial'>further confirmation command (continue or abort).</font></pre></span> <span name = "INTRA" style='top:589px; left:466px' class="ft0"><pre><font face='Arial'>merely addresses. A route would be</font></pre></span> <span name = "INTRA" style='top:601px; left:466px' class="ft0"><pre><font face='Arial'>expressed in the form RCPT TO:</font></pre></span> <span name = "INTRA" style='top:606px; left:88px' class="ft0"><pre><font face='Arial'>2xx: Positive Completion Reply. Command completed. Awaiting next com </font></pre></span> <span name = "INTRA" style='top:613px; left:466px' class="ft0"><pre><font face='Arial'><server1,server2:someone@server3> .</font></pre></span> <span name = "INTRA" style='top:618px; left:88px' class="ft0"><pre><font face='Arial'>mand.</font></pre></span> <span name = "INTRA" style='top:625px; left:466px' class="ft0"><pre><font face='Arial'>Today this capability is rarely needed.</font></pre></span> <span name = "INTRA" style='top:637px; left:88px' class="ft0"><pre><font face='Arial'>3xx: Positive Intermediate Reply. Command accepted but held awaiting</font></pre></span> <span name = "INTRA" style='top:649px; left:88px' class="ft0"><pre><font face='Arial'>further information (such as a password).</font></pre></span> <span name = "INTRA" style='top:650px; left:466px' class="ft1"><pre><font face='Arial'><i><b>Message</b></i> <i><b>Text</b></i></font></pre></span> <span name = "INTRA" style='top:669px; left:88px' class="ft0"><pre><font face='Arial'>4xx: Transient Negative Completion Reply. Command not accepted due to</font></pre></span> <span name = "INTRA" style='top:673px; left:480px' class="ft0"><pre><font face='Arial'>Once all the recipients have been</font></pre></span> <span name = "INTRA" style='top:681px; left:88px' class="ft0"><pre><font face='Arial'>a temporary error condition (such as an HTTP server busy). The command</font></pre></span> <span name = "INTRA" style='top:685px; left:466px' class="ft0"><pre><font face='Arial'>specified, all that remains is for the</font></pre></span> <span name = "INTRA" style='top:693px; left:88px' class="ft0"><pre><font face='Arial'>may be tried again later.</font></pre></span> <span name = "INTRA" style='top:697px; left:466px' class="ft0"><pre><font face='Arial'>sender to send the message itself. First</font></pre></span> <span name = "INTRA" style='top:709px; left:466px' class="ft0"><pre><font face='Arial'>it sends the command DATA , and</font></pre></span> <span name = "INTRA" style='top:713px; left:88px' class="ft0"><pre><font face='Arial'>5xx: Permanent Negative Completion Reply. Command not accepted due to</font></pre></span> <span name = "INTRA" style='top:721px; left:466px' class="ft0"><pre><font face='Arial'>then waits for a reply like: 354 Start</font></pre></span> <span name = "INTRA" style='top:725px; left:88px' class="ft0"><pre><font face='Arial'>a permanent error condition. The command is unlikely to be accepted if</font></pre></span> <span name = "INTRA" style='top:733px; left:466px' class="ft0"><pre><font face='Arial'>mail input; end with <CRLF>. </font></pre></span> <span name = "INTRA" style='top:737px; left:88px' class="ft0"><pre><font face='Arial'>repeated later.</font></pre></span> <span name = "INTRA" style='top:745px; left:466px' class="ft0"><pre><font face='Arial'><CRLF> . The message is then sent as</font></pre></span> <span name = "INTRA" style='top:758px; left:88px' class="ft0"><pre><font face='Arial'>Second Digit</font></pre></span> <span name = "INTRA" style='top:757px; left:466px' class="ft0"><pre><font face='Arial'>a succession of lines of text. No ac </font></pre></span> <span name = "INTRA" style='top:769px; left:466px' class="ft0"><pre><font face='Arial'>knowledgement is received for each</font></pre></span> <span name = "INTRA" style='top:773px; left:88px' class="ft0"><pre><font face='Arial'>x0x: Syntax Error. For example, command unimplemented or valid but</font></pre></span> <span name = "INTRA" style='top:781px; left:466px' class="ft0"><pre><font face='Arial'>line, though the sender needs to watch</font></pre></span> <span name = "INTRA" style='top:785px; left:88px' class="ft0"><pre><font face='Arial'>incorrect in the circumstances.</font></pre></span> <span name = "INTRA" style='top:793px; left:466px' class="ft0"><pre><font face='Arial'>for a reply that indicates an error con </font></pre></span> <span name = "INTRA" style='top:805px; left:88px' class="ft0"><pre><font face='Arial'>x1x: Information. The text following the code contains the answer to an</font></pre></span> <span name = "INTRA" style='top:805px; left:466px' class="ft0"><pre><font face='Arial'>dition.</font></pre></span> <span name = "INTRA" style='top:817px; left:88px' class="ft0"><pre><font face='Arial'>information request.</font></pre></span> <span name = "INTRA" style='top:817px; left:480px' class="ft0"><pre><font face='Arial'>The end of the message is, as indi </font></pre></span> <span name = "INTRA" style='top:829px; left:466px' class="ft0"><pre><font face='Arial'>cated by the reply shown above, a pe </font></pre></span> <span name = "INTRA" style='top:837px; left:88px' class="ft0"><pre><font face='Arial'>x2x: Connections. Message reply relates to the communications channel.</font></pre></span> <span name = "INTRA" style='top:841px; left:466px' class="ft0"><pre><font face='Arial'>riod (full stop) on a line of its own.</font></pre></span> <span name = "INTRA" style='top:853px; left:466px' class="ft0"><pre><font face='Arial'>Thus, one of the simplest but most es </font></pre></span> <span name = "INTRA" style='top:857px; left:88px' class="ft0"><pre><font face='Arial'>x5x: Server. Message reply relates to the state of the server.</font></pre></span> <span name = "INTRA" style='top:865px; left:466px' class="ft0"><pre><font face='Arial'>sential things that a mail client must do</font></pre></span> <span name = "INTRA" style='top:877px; left:88px' class="ft0"><pre><font face='Arial'>Third Digit</font></pre></span> <span name = "INTRA" style='top:877px; left:466px' class="ft0"><pre><font face='Arial'>is ensure that a line containing a single</font></pre></span> <span name = "INTRA" style='top:889px; left:466px' class="ft0"><pre><font face='Arial'>period does not appear in the actual</font></pre></span> <span name = "INTRA" style='top:893px; left:88px' class="ft0"><pre><font face='Arial'>Used to distinguish individual messages.</font></pre></span> <span name = "INTRA" style='top:901px; left:466px' class="ft0"><pre><font face='Arial'>text.</font></pre></span> <span name = "INTRA" style='top:946px; left:52px' class="ft0"><pre><font face='Arial'>File: C04100.14</font></pre></span> <span name = "INTRA" style='top:946px; left:534px' class="ft0"><pre><font face='Arial'>Issue 93 (March 1998) page 16</font></pre></span> <span name = "INTRA" style='top:944px; left:260px' class="ft2"><pre><font face='Arial'><i>PC</i> <i>Network</i> <i>Advisor</i></font></pre></span> <span name = "INTRA" class='nav' style='left: 357px; top: 1010px'><pre><a href='page0001.htm'><</a> Next page <a href='page0003.htm'>></a></pre></span> <span name = "INTRA" style='top:1050px; left:50px' class="ft4"><pre><b><font color="#FF0000" size="3" face="Arial">New!</font><font color="#FF0000" size="3" face="Arial Narrow"> </font><font size="2" face="Arial">The best sites for quality <a href="http://www.inkjet-printer-cartridges.org">inkjet printer cartridges</a> and the best sites for <a href="http://www.cheap-inkjet-cartridges.com">cheap inkjet cartridges</a></font></b></pre></span></body> <span name = "INTRA" style='top:1100px; left:300px' class="ft4"><pre><b><font color="#FF0000" size="3" face="Arial"><a href="../index.html">Windows Help Desk Home</a> </font></b></pre></span></body></html>