<?xml version="1.0"?> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/><title>couriertcpd</title><link rel="stylesheet" href="style.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.74.0"/><link rel="home" href="#couriertcpd" title="couriertcpd"/><link xmlns="" rel="stylesheet" type="text/css" href="manpage.css"/><meta xmlns="" name="MSSmartTagsPreventParsing" content="TRUE"/><link xmlns="" rel="icon" href="icon.gif" type="image/gif"/><!-- Copyright 1998 - 2009 Double Precision, Inc. See COPYING for distribution information. --></head><body><div class="refentry" lang="en" xml:lang="en"><a id="couriertcpd" shape="rect"> </a><div class="titlepage"/><div class="refnamediv"><h2>Name</h2><p>couriertcpd — the <span class="application">Courier</span> mail server TCP server daemon</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">couriertcpd</code> [-pid=<em class="replaceable"><code>pidfile</code></em>] [<em class="replaceable"><code>option</code></em>...] {<em class="replaceable"><code>list</code></em>} {<em class="replaceable"><code>program</code></em>} {<em class="replaceable"><code>arg</code></em>...}</p></div><div class="cmdsynopsis"><p><code class="command">couriertcpd</code> {-pid=<em class="replaceable"><code>pidfile</code></em>} {-stop}</p></div><div class="cmdsynopsis"><p><code class="command">couriertcpd</code> {-pid=<em class="replaceable"><code>pidfile</code></em>} {-restart}</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="id331480" shape="rect"> </a><h2>DESCRIPTION</h2><p> <span class="command"><strong>couriertcpd</strong></span> accepts incoming network connections, and runs <span class="command"><strong>program</strong></span> after establishing each network connection. The <span class="command"><strong>program</strong></span>'s standard input and output are set to the network connection.</p><p> <em class="replaceable"><code>list</code></em> is a comma-separated list of TCP port numbers where incoming connections are created. <span class="command"><strong>program</strong></span> is the program to run. If <span class="command"><strong>program</strong></span> requires any arguments, they are specified on the command line, after <span class="command"><strong>program</strong></span> itself.</p><p> Before running <span class="command"><strong>program</strong></span>, <span class="command"><strong>couriertcpd</strong></span> initializes several environment variables that describe the network connection. The environment inherited by <span class="command"><strong>program</strong></span> will be the environment inherited by <span class="command"><strong>couriertcpd</strong></span>, plus any additional environment variables initialized by <span class="command"><strong>couriertcpd</strong></span>. It is also possible to reject certain network connections. Several options are available to specify which network connections will be rejected.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="id330485" shape="rect"> </a><h2>OPTIONS</h2><div class="variablelist"><dl><dt><span class="term">-access=<em class="replaceable"><code>filename</code></em></span></dt><dd><p> Specifies an optional access file. The access file lists the IP addresses from which connections should be accepted or rejected. The access file is also used to initialize environment variables based on the IP address of the connection. <em class="replaceable"><code>filename</code></em> is a GDBM or DB database file that's usually created by a script from one or more text files. See "ACCESS FILE" below for more information.</p></dd><dt><span class="term">-accesslocal</span></dt><dd><p> Lookup the local interface IP and port in the access file, in addition to looking up the remote IP. This gives a mechanism for setting environment variables depending on which IP address and/or port the client connected to. In the access file, "1.2.3.4.25" matches connections to IP address 1.2.3.4 port 25; "1.2.3.4" matches connections to IP address 1.2.3.4 on any port; and "*.25" matches connections to port 25 on any IP address.</p></dd><dt><span class="term">-address=<em class="replaceable"><code>n.n.n.n</code></em></span></dt><dd><p> Accept network connections only to IP address <em class="replaceable"><code>n.n.n.n</code></em>. If not specified, <span class="command"><strong>couriertcpd</strong></span> accepts connections to any IP address that the system accepts connections on. If the system has multiple network interfaces with separate IP addresses, this option makes <span class="command"><strong>couriertcpd</strong></span> accept connections only to one specific IP address. Most systems have multiple network interfaces: the loopback interface, plus the local network interface, so that <code class="literal">-address=127.0.0.1</code> accepts connections only from the local system. When multiple port numbers are specified, it is also possible to selectively bind different network addresses to each port number when <em class="replaceable"><code>list</code></em> specifies more than one port number. See "<a class="ulink" href="#list" target="_top" shape="rect">Multiple port list</a>" below for more information.</p></dd><dt><span class="term">-block=<em class="replaceable"><code>zone</code></em>[,<em class="replaceable"><code>var</code></em>[/<em class="replaceable"><code>n.n.n.n</code></em>][,<em class="replaceable"><code>msg</code></em>]]</span></dt><dd><p> Initialize the environment variable <em class="replaceable"><code>var</code></em> if both of the following conditions are true: <em class="replaceable"><code>var</code></em> is not already initialized; the connecting IP address can be found in a DNS-based list. See DNS ACCESS LISTS, below. Multiple <code class="option">-block</code> options can be used.</p></dd><dt><span class="term">-denymsg=<em class="replaceable"><code>text</code></em></span></dt><dd><p> Specifies an optional message to be returned to the client if the <em class="parameter"><code>-access</code></em> option rejects them. The default is to drop the TCP connection without sending back any messages.</p></dd><dt><span class="term">-group=<em class="replaceable"><code>group</code></em></span></dt><dd><p> Set <span class="command"><strong>couriertcpd</strong></span>'s its group ID. <em class="replaceable"><code>group</code></em> may be specified numerically, or by its name. Only the superuser may use <code class="option">-group</code>.</p></dd><dt><span class="term">-listen=<em class="replaceable"><code>n</code></em></span></dt><dd><p> Length of the queue which holds pending connections. <em class="replaceable"><code>n</code></em> is a number. If not specified, the system default is used.</p></dd><dt><span class="term">-maxperc=<em class="replaceable"><code>n</code></em></span></dt><dd><p> Maximum number of connections accepted from the same C network block. Using this option is recommended, because connection slots are limited. Without this option, the same C network block can potentially use up all available connection slots.</p></dd><dt><span class="term">-maxperip=<em class="replaceable"><code>n</code></em></span></dt><dd><p> Maximum number of connections accepted from the same IP address. Use both the <code class="option">-maxperc</code> and <code class="option">-maxperip</code> options to fine tune connection limits. For example, when <span class="command"><strong>couriertcpd</strong></span> is listening on the SMTP port it makes sense to set an upper limit on the number of connections from the same C block. Domains that send a large amount of mail often have multiple servers sending outbound mail from the same C block, so it makes sense to set limits on individual C blocks. On the other hand, if <span class="command"><strong>couriertcpd</strong></span> is listening on the POP3 port it makes more sense to set limits on individual IP addresses. If a C block of addresses is assigned to a dialup modem pool, it is certainly possible to have many IP addresses within the same C block have connections to the POP3 server at the same time.</p></dd><dt><span class="term">-maxprocs=<em class="replaceable"><code>n</code></em></span></dt><dd><p> Maximum number of connection slots, or the maximum number of processes started. This effectively specifies the maximum number of connections accepted at the same time. After the maximum number of connections has been opened, <span class="command"><strong>couriertcpd</strong></span> waits for an existing connection to close, before accepting any more connections.</p></dd><dt><span class="term">-warn=<em class="replaceable"><code>n</code></em></span></dt><dd><p> Log a <span class="errorcode">LOG_WARNING</span> message to syslog when the number of active processes exceeds <em class="replaceable"><code>n</code></em>. The default is 90% of <em class="replaceable"><code>maxprocs</code></em>. <span class="command"><strong>couriertcpd</strong></span> logs a <span class="errorcode">LOG_ALERT</span> syslog message when the number of active processes reaches the maximum.</p></dd><dt><span class="term">-nodnslookup</span></dt><dd><p> Do not look up the hostname associated with connecting IP address and the local addres, do not initialize the <code class="envar">TCPREMOTEHOST</code> or <code class="envar">TCPLOCALHOST</code> environment variables (see below).</p></dd><dt><span class="term">-noidentlookup</span></dt><dd><p> Do not perform an <span class="emphasis"><em>ident</em></span> lookup, and do not initialize the <code class="envar">TCPREMOTEINFO</code> environment variable.</p></dd><dt><span class="term">-pid=<em class="replaceable"><code>filename</code></em></span></dt><dd><p> If given, <span class="command"><strong>couriertcpd</strong></span> puts itself into the background and saves its process ID in this file, usually somewhere in <code class="filename">/var/run</code>.</p><p>This option must also be present when using the <code class="option">-restart</code> and <code class="option">-stop</code> options.</p></dd><dt><span class="term">-restart</span></dt><dd><p> Send a SIGHUP to an existing <span class="command"><strong>couriertcpd</strong></span> process. Specify the same <code class="option">-pid</code> argument as the one that was used to start <span class="command"><strong>couriertcpd</strong></span>. The process ID is read from the <code class="option">-pid</code> file, and the <span class="command"><strong>couriertcpd</strong></span> receives a SIGHUP signal.</p></dd><dt><span class="term">-stderr=socket</span></dt><dd><p> Set <span class="command"><strong>program</strong></span>'s standard error to the network connection, just like its standard input and output.</p></dd><dt><span class="term">-stderr=<em class="replaceable"><code>logfile</code></em></span></dt><dd><p> Set <span class="command"><strong>program</strong></span>'s standard error to the specified file, <code class="filename">logfile</code>. The file is created, if necessary, and is opened in append mode.</p></dd><dt><span class="term">-stderrlogger=<em class="replaceable"><code>logprogram</code></em></span></dt><dd><p> Set <span class="command"><strong>program</strong></span>'s standard error to a pipe, which is read by <span class="command"><strong>logprogram</strong></span>. Only one instance of <em class="replaceable"><code>logger</code></em> is started, which receives standard error from every instance of <span class="command"><strong>program</strong></span>. The specified <em class="replaceable"><code>logger</code></em> is executed with the output end of the stderr pipe connected as standard input. <em class="replaceable"><code>logprogram</code></em> is executed with one argument - <span class="command"><strong>program</strong></span>'s name.</p></dd><dt><span class="term">-stderrloggername=name</span></dt><dd><p> Use <em class="replaceable"><code>name</code></em> as the argument to <em class="replaceable"><code>logprogram</code></em>, instead of the <span class="command"><strong>program</strong></span>'s name.</p></dd><dt><span class="term">-stop</span></dt><dd><p> Stop (kill) an existing <span class="command"><strong>couriertcpd</strong></span> process. Specify the same <code class="option">-pid</code> argument as the one that was used to start <span class="command"><strong>couriertcpd</strong></span>. The process ID is read from the <code class="option">-pid</code> file, and the <span class="command"><strong>couriertcpd</strong></span> process is killed. All child processes of <span class="command"><strong>couriertcpd</strong></span> will receive a SIGTERM signal.</p></dd><dt><span class="term">-user=<em class="replaceable"><code>user</code></em></span></dt><dd><p> Set <span class="command"><strong>couriertcpd</strong></span>'s user ID. Also, the group ID is set to the user's group ID. Using both <code class="option">-group</code> and <code class="option">-user</code> is not necessary. Only the superuser can specify <code class="option">-user</code>.</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="id375376" shape="rect"> </a><h2>MULTIPLE PORT LIST</h2><a id="list" shape="rect"> </a><p> The <em class="replaceable"><code>list</code></em> argument can be a comma-separated list of multiple port numbers. <span class="command"><strong>couriertcpd</strong></span> will create network connections on any listed port. Each port number can be optionally specified as "address.port", for example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> couriertcpd -pid=/var/run/smtp.pid 127.0.0.1.25,999 <em class="replaceable"><code>program</code></em> </pre></div><p> This instance accepts network connections to either port 25 or port 999, however connections on port 25 are created only on the IP address 127.0.0.1, the loopback interface.</p><p>Whenever an IP address is not specified, network connections are accepted to any IP address (called "wildcarding"). On IPv6-capable systems, <span class="command"><strong>couriertcpd</strong></span> will attempt to create two incoming network connection ports, if an IP address is not specified. After creating the first port as an IPv6 wildcard port, couriertcpd will then attept to create an IPv4 wildcard port, with the same port number. Some BSD-derived systems must use separate IPv6 and IPv4 wildcard ports to create incoming network connections. Most other systems only need an IPv6 port to create both IPv6 and IPv4 incoming network connections. <span class="command"><strong>couriertcpd</strong></span> quietly ignores a failure to create an IPv4 wildcard port, as long as an IPv6 wildcard was succesfully created.</p><p> The <code class="option">-address</code> option can be used to default a specific IP address for every listed port number. For example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> couriertcpd -pid=/var/run/smtp.pid 127.0.0.1.25,127.0.0.1.999 <em class="replaceable"><code>program</code></em> </pre></div><p> and</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> couriertcpd -pid=/var/run/smtp.pid -address=127.0.0.1 25,999 <em class="replaceable"><code>program</code></em> </pre></div><p> will create network connections on ports 25 and 999 of the IP address 127.0.0.1.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="id375476" shape="rect"> </a><h2>ACCESS FILE</h2><p> The access file lists IP addresses that <span class="command"><strong>couriertcpd</strong></span> will accept or reject connections from. An access file is optional. Without an access file <span class="command"><strong>couriertcpd</strong></span> accepts a connection from any IP address.</p><p> Both IPv4 and IPv6 addresses can be specified, if IPv6 support is available. A non-standard syntax is currently used to specify IPv6 addresses. This is subject to change in the near future. IPv6 support is currently considered to be experimental.</p><p> The access file is a binary database file that's usually created by a script, such as <a class="ulink" href="makesmtpaccess.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">makesmtpaccess</span>(8)</span></a>, from one or more plain text files. Blank lines in the text file are ignored. Lines that start with the # character are also ignored.</p><div class="refsect2" lang="en" xml:lang="en"><a id="id375516" shape="rect"> </a><h3>Rejecting and accepting connections by IP address</h3><p> The following line instructs <span class="command"><strong>couriertcpd</strong></span> to reject all connections from an IP address range:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> netblock<tab>deny </pre></div><p><em class="replaceable"><code>netblock</code></em> is an IP address, such as <code class="literal">192.68.0.2</code>. <span class="token"><tab></span> is the ASCII tab character. There MUST be exactly one tab character after the IP address and the word "deny".</p><p> You can also block connections from an entire network C block:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> 192.68.0<tab>deny </pre></div><p> This blocks connections from IP addresses <code class="literal">192.68.0.0</code> through <code class="literal">192.68.0.255</code>. Blocking connections from an entire B or A network block works the same way.</p><p> Use the word "<code class="literal">allow</code>" instead of "<code class="literal">deny</code>" to explicitly allow connections from that IP address or netblock. For example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> 192.68.0<tab>deny 192.68.0.10<tab>allow </pre></div><p> This blocks all connections from <code class="literal">192.68.0.0</code> to <code class="literal">192.68.0.255</code> except for <code class="literal">192.68.0.10</code>. These two lines can occur in any order. <span class="command"><strong>couriertcpd</strong></span> always uses the line with the most specific IP address.</p><p> If the IP address of the connection is not found in the access file the connection is accepted by default. The following line causes unlisted connections to be rejected:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> *<tab>deny </pre></div></div><div class="refsect2" lang="en" xml:lang="en"><a id="id375642" shape="rect"> </a><h3>IPv6 addresses</h3><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> IPv6 support in the access file is experimental, and is subject to change in a future release. The following syntax is subject to change at any time.</p></div><p> The access file can also specify IPv6 addresses, if IPv6 support is available. The existing IPv4 address format is used for IPv6-mapped IPv4 addresses, and no changes are required. For all other IPv6 addresses use the following format:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> :hhhh:hhhh:hhhh:hhhh:hhhh:hhhh:hhhh:hhhh<tab><em class="replaceable"><code>action</code></em> </pre></div><p> The IPv6 address must begin with :. The initial : character is not really a part of the IPv6 address, it is only used to designate this record as an IPv6 address, allowing an access file to contain a mixture of IPv4 and IPv6 addresses. The IPv6 address follows the initial : character, and it must be spelled out <span class="emphasis"><em>using zero-padded lowercase hexadecimal digits</em></span>. For example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> :0000:0000:0000:0000:0000:f643:00a2:9354<tab>deny </pre></div><p> Netblocks must be specified using even-word boundaries only:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> :3ffe<tab>deny </pre></div><p> This will deny entire 3ffe::/16 (6bone network, which is phased out). </p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> :2002:c0a8<tab>deny </pre></div><p> This will deny 2002:c0a8::/32 (6to4 addresses derived from private address space).</p></div><div class="refsect2" lang="en" xml:lang="en"><a id="id375721" shape="rect"> </a><h3>Setting environment variables</h3><p> <code class="literal">allow</code> can be optionally followed by a list of environment variable assignments, separated by commas. The environment variables are set before executing <span class="command"><strong>program</strong></span> or checking access lists (see below). For example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> 192.68.0<tab>allow,RELAYCLIENT 192.68.0.10<tab>allow,RELAYCLIENT,SIZELIMIT=1000000 </pre></div><p> This sets <code class="envar">RELAYCLIENT</code> environment variable for connections from the <code class="literal">192.68.0</code> block. In addition to that, the <code class="envar">SIZELIMIT</code> environment variable is set to <code class="literal">1000000</code> if the connection comes from the IP address <code class="literal">192.68.0.10</code>.</p><p> Note that <code class="envar">RELAYCLIENT</code> must be explicitly specified for the IP address <code class="literal">192.68.0.10</code>. The first line is NOT used for connections from this IP address. <span class="command"><strong>couriertcpd</strong></span> only reads one entry from the access file, the entry for the most specific IP address.</p></div><div class="refsect2" lang="en" xml:lang="en"><a id="id375795" shape="rect"> </a><h3>DNS ACCESS LISTS</h3><p>An alternative to listing banned IP addresses is to use an external DNS-based IP access list.</p><p> There is no provision to support IPv6-based lists, because none yet exist. IPv6-based access list support will be added in the future.</p><p> <span class="command"><strong>couriertcpd</strong></span> does not automatically reject connections from any IP address listed on a DNS-based list. If the connecting IP address is listed couriertcpd simply sets an environment variable. It's up to the <span class="command"><strong>program</strong></span>, run by <span class="command"><strong>couriertcpd</strong></span>, to read the environment variable and choose what to do if the environment variable is set.</p><p>Please note that if the environment variable is already set, <span class="command"><strong>couriertcpd</strong></span> will NOT search the access list. This can be used to override the access list where <span class="command"><strong>program</strong></span> only recognizes the access list if the environment variable is not empty. By setting the environment variable to an empty string in the access file (see above), you can override access lists for selected IP addresses.</p><p> The <code class="option">-block</code> option queries a DNS list for each connecting IP address. The only required argument to <code class="option">-block</code> is the DNS zone that is used to publish thelist. The name of the zone can optionally be followed by a comma and the name of the environment variable to set if the DNS list includes the IP address. <span class="command"><strong>couriertcpd</strong></span> sets the environment variable <code class="envar">BLOCK</code> if you do not specify the name yourself.</p><p> The name of the environment variable can be optionally followed by a slash and an IP address. Normally <span class="command"><strong>couriertcpd</strong></span> sets the environment variable if the access list includes any A record entry for the specified IP address. Some access lists may offer additional information by returning one of several possible A records. If the name of the environment variable is followed by a slash and an IP address, the environment variable will be initialized only if the access list includes an A record containing the indicated IP address.</p><p> The contents of the environment variable will be the contents of any TXT record for the listed IP address. <em class="replaceable"><code>var</code></em>[/<em class="replaceable"><code>n.n.n.n</code></em>] can be optionally followed by a comma and a text message, which will be used instead of the TXT record. The text message may include a single @ character somewhere in it, which will be replaced by the listed IP address.</p></div><div class="refsect2" lang="en" xml:lang="en"><a id="id375895" shape="rect"> </a><h3>MULTIPLE DNS LISTS</h3><p> Multiple <code class="option">-block</code> options can be used. The connecting IP address will be looked up in multiple access lists. This is implemented as follows.</p><p> <span class="command"><strong>couriertcpd</strong></span> processes all <code class="option">-block</code> options one at a time. If the indicated environment variable is already set, <span class="command"><strong>couriertcpd</strong></span> skips the DNS list lookup (this is also true if only one <code class="option">-block</code> option is specified). Therefore, if multiple <code class="option">-block</code> options are used, and an IP address is found in the first access list, the remaininglists that use the same environment variable will not be checked. But other lists that use a different environment variable WILL be checked.</p><p> The same <em class="replaceable"><code>zone</code></em> can be specified more than once, with different environment variables and different IP addresses. For example:</p><div class="informalexample"><pre class="programlisting" xml:space="preserve"> couriertcpd -block=block.example.org,BLOCK1/127.0.0.2 \ -block=block.example.org,BLOCK2/127.0.0.3 </pre></div><p> If the specified access list contains an A record for the listed address, and the A record contains the IP address 127.0.0.2, <span class="command"><strong>couriertcpd</strong></span> initializes the <code class="envar">BLOCK1</code> environment variable. If the A record contains the IP address 127.0.0.3, <span class="command"><strong>couriertcpd</strong></span> initializes <code class="envar">BLOCK2</code>. If both records are present, both variables are initialized.</p><p> <span class="command"><strong>couriertcpd</strong></span> uses the following logic to determine what kind of DNS query to issue:</p><p> If neither the IP address, nor <em class="replaceable"><code>msg</code></em> is specified, <span class="command"><strong>couriertcpd</strong></span> will query for existence of TXT records, for the IP address.</p><p> If only <em class="replaceable"><code>msg</code></em> is specified, <span class="command"><strong>couriertcpd</strong></span> looks up the existence of A records, for the IP address.</p><p> If <em class="replaceable"><code>/n.n.n.n</code></em> is used, and <em class="replaceable"><code>msg</code></em> is not specified for at least one <code class="option">-block</code> option for this same zone, <span class="command"><strong>couriertcpd</strong></span> will query for existence of ANY records, which should return both TXT and all the A records for this IP address.</p><p> If <em class="replaceable"><code>/n.n.n.n</code></em> is used, and <em class="replaceable"><code>msg</code></em> is specified for every <code class="option">-block</code> option for this same zone, <span class="command"><strong>couriertcpd</strong></span> will query for existence of A records only.</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="id376047" shape="rect"> </a><h2>ENVIRONMENT VARIABLES</h2><p> <span class="command"><strong>couriertcpd</strong></span> also initializes the following environment variables prior to running <span class="command"><strong>program</strong></span>:</p><div class="variablelist"><dl><dt><span class="term">TCPLOCALHOST</span></dt><dd><p> The name of the host on the local end of the network connection, looked up in DNS. <code class="envar">TCPLOCALHOST</code> will not be set if the IP address of the network connection's local end cannot be found in DNS, or if <code class="option">-nodnslookup</code> option is specified. <code class="envar">TCPLOCALHOST</code> will be set to the string <span class="errorcode">softdnserr</span> if the DNS lookup fails with a temporary error (so you cannot tell if the IP address has a valid host name associated with it), or if the reverse and forward DNS lookups do not match. <code class="envar">TCPLOCALHOST</code> will not be set if the reverse DNS lookup fails completely.</p></dd><dt><span class="term">TCPLOCALIP</span></dt><dd><p> The IP address of the local end of the network connection.</p></dd><dt><span class="term">TCPLOCALPORT</span></dt><dd><p> Rhe number of the port of the local end of the network connection.</p></dd><dt><span class="term">TCPREMOTEHOST</span></dt><dd><p> The hostname of the connecting host. Like <code class="envar">TCPLOCALHOST</code>, but for the connecting IP address.</p></dd><dt><span class="term">TCPREMOTEIP</span></dt><dd><p> Connecting IP address.</p></dd><dt><span class="term">TCPREMOTEINFO</span></dt><dd><p> Identification string received from the IDENT server on the remote IP address. Not set if the IDENT server returned an error, or if the <code class="option">-noidentlookup</code> option was specified.</p></dd><dt><span class="term">TCPREMOTEPORT</span></dt><dd><p> TCP port of the remote end of the network connection.</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="id376191" shape="rect"> </a><h2>SEE ALSO</h2><p> <a class="ulink" href="courier.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">courier</span>(8)</span></a>.</p></div></div></body></html>