1<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3<html> <head> 4<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 5<title> Postfix manual - verify(8) </title> 6</head> <body> <pre> 7VERIFY(8) VERIFY(8) 8 9<b>NAME</b> 10 verify - Postfix address verification server 11 12<b>SYNOPSIS</b> 13 <b>verify</b> [generic Postfix daemon options] 14 15<b>DESCRIPTION</b> 16 The <a href="verify.8.html"><b>verify</b>(8)</a> address verification server maintains a 17 record of what recipient addresses are known to be deliv- 18 erable or undeliverable. 19 20 Addresses are verified by injecting probe messages into 21 the Postfix queue. Probe messages are run through all the 22 routing and rewriting machinery except for final delivery, 23 and are discarded rather than being deferred or bounced. 24 25 Address verification relies on the answer from the nearest 26 MTA for the specified address, and will therefore not 27 detect all undeliverable addresses. 28 29 The <a href="verify.8.html"><b>verify</b>(8)</a> server is designed to run under control by 30 the Postfix master server. It maintains an optional per- 31 sistent database. To avoid being interrupted by "postfix 32 stop" in the middle of a database update, the process runs 33 in a separate process group. 34 35 The <a href="verify.8.html"><b>verify</b>(8)</a> server implements the following requests: 36 37 <b>update</b> <i>address status text</i> 38 Update the status and text of the specified 39 address. 40 41 <b>query</b> <i>address</i> 42 Look up the <i>status</i> and <i>text</i> for the specified 43 address. If the status is unknown, a probe is sent 44 and an "in progress" status is returned. 45 46<b>SECURITY</b> 47 The address verification server is not security-sensitive. 48 It does not talk to the network, and it does not talk to 49 local users. The verify server can run chrooted at fixed 50 low privilege. 51 52 The address verification server can be coerced to store 53 unlimited amounts of garbage. Limiting the cache size 54 trades one problem (disk space exhaustion) for another one 55 (poor response time to client requests). 56 57 With Postfix version 2.5 and later, the <a href="verify.8.html"><b>verify</b>(8)</a> server 58 no longer uses root privileges when opening the 59 <b><a href="postconf.5.html#address_verify_map">address_verify_map</a></b> cache file. The file should now be 60 stored under the Postfix-owned <b><a href="postconf.5.html#data_directory">data_directory</a></b>. As a 61 migration aid, an attempt to open a cache file under a 62 non-Postfix directory is redirected to the Postfix-owned 63 <b><a href="postconf.5.html#data_directory">data_directory</a></b>, and a warning is logged. 64 65<b>DIAGNOSTICS</b> 66 Problems and transactions are logged to <b>syslogd</b>(8). 67 68<b>BUGS</b> 69 The address verification service is suitable only for 70 sites that handle a low mail volume. Verification probes 71 add additional traffic to the mail queue and perform 72 poorly under high load. Servers may blacklist sites that 73 probe excessively, or that probe excessively for non-exis- 74 tent recipient addresses. 75 76 If the persistent database ever gets corrupted then the 77 world comes to an end and human intervention is needed. 78 This violates a basic Postfix principle. 79 80<b>CONFIGURATION PARAMETERS</b> 81 Changes to <a href="postconf.5.html"><b>main.cf</b></a> are not picked up automatically, as 82 <a href="verify.8.html"><b>verify</b>(8)</a> processes are persistent. Use the command "<b>post-</b> 83 <b>fix reload</b>" after a configuration change. 84 85 The text below provides only a parameter summary. See 86 <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples. 87 88<b>CACHE CONTROLS</b> 89 <b><a href="postconf.5.html#address_verify_map">address_verify_map</a> (empty)</b> 90 Optional lookup table for persistent address veri- 91 fication status storage. 92 93 <b><a href="postconf.5.html#address_verify_sender">address_verify_sender</a> ($<a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a>)</b> 94 The sender address to use in address verification 95 probes; prior to Postfix 2.5 the default was "post- 96 master". 97 98 <b><a href="postconf.5.html#address_verify_positive_expire_time">address_verify_positive_expire_time</a> (31d)</b> 99 The time after which a successful probe expires 100 from the address verification cache. 101 102 <b><a href="postconf.5.html#address_verify_positive_refresh_time">address_verify_positive_refresh_time</a> (7d)</b> 103 The time after which a successful address verifica- 104 tion probe needs to be refreshed. 105 106 <b><a href="postconf.5.html#address_verify_negative_cache">address_verify_negative_cache</a> (yes)</b> 107 Enable caching of failed address verification probe 108 results. 109 110 <b><a href="postconf.5.html#address_verify_negative_expire_time">address_verify_negative_expire_time</a> (3d)</b> 111 The time after which a failed probe expires from 112 the address verification cache. 113 114 <b><a href="postconf.5.html#address_verify_negative_refresh_time">address_verify_negative_refresh_time</a> (3h)</b> 115 The time after which a failed address verification 116 probe needs to be refreshed. 117 118<b>PROBE MESSAGE ROUTING CONTROLS</b> 119 By default, probe messages are delivered via the same 120 route as regular messages. The following parameters can 121 be used to override specific message routing mechanisms. 122 123 <b><a href="postconf.5.html#address_verify_relayhost">address_verify_relayhost</a> ($<a href="postconf.5.html#relayhost">relayhost</a>)</b> 124 Overrides the <a href="postconf.5.html#relayhost">relayhost</a> parameter setting for 125 address verification probes. 126 127 <b><a href="postconf.5.html#address_verify_transport_maps">address_verify_transport_maps</a> ($<a href="postconf.5.html#transport_maps">transport_maps</a>)</b> 128 Overrides the <a href="postconf.5.html#transport_maps">transport_maps</a> parameter setting for 129 address verification probes. 130 131 <b><a href="postconf.5.html#address_verify_local_transport">address_verify_local_transport</a> ($<a href="postconf.5.html#local_transport">local_transport</a>)</b> 132 Overrides the <a href="postconf.5.html#local_transport">local_transport</a> parameter setting for 133 address verification probes. 134 135 <b><a href="postconf.5.html#address_verify_virtual_transport">address_verify_virtual_transport</a> ($<a href="postconf.5.html#virtual_transport">virtual_transport</a>)</b> 136 Overrides the <a href="postconf.5.html#virtual_transport">virtual_transport</a> parameter setting 137 for address verification probes. 138 139 <b><a href="postconf.5.html#address_verify_relay_transport">address_verify_relay_transport</a> ($<a href="postconf.5.html#relay_transport">relay_transport</a>)</b> 140 Overrides the <a href="postconf.5.html#relay_transport">relay_transport</a> parameter setting for 141 address verification probes. 142 143 <b><a href="postconf.5.html#address_verify_default_transport">address_verify_default_transport</a> ($<a href="postconf.5.html#default_transport">default_transport</a>)</b> 144 Overrides the <a href="postconf.5.html#default_transport">default_transport</a> parameter setting 145 for address verification probes. 146 147<b>MISCELLANEOUS CONTROLS</b> 148 <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b> 149 The default location of the Postfix <a href="postconf.5.html">main.cf</a> and 150 <a href="master.5.html">master.cf</a> configuration files. 151 152 <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b> 153 How much time a Postfix daemon process may take to 154 handle a request before it is terminated by a 155 built-in watchdog timer. 156 157 <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b> 158 The time limit for sending or receiving information 159 over an internal communication channel. 160 161 <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b> 162 The process ID of a Postfix command or daemon 163 process. 164 165 <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b> 166 The process name of a Postfix command or daemon 167 process. 168 169 <b><a href="postconf.5.html#queue_directory">queue_directory</a> (see 'postconf -d' output)</b> 170 The location of the Postfix top-level queue direc- 171 tory. 172 173 <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b> 174 The syslog facility of Postfix logging. 175 176 <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b> 177 The mail system name that is prepended to the 178 process name in syslog records, so that "smtpd" 179 becomes, for example, "postfix/smtpd". 180 181<b>SEE ALSO</b> 182 <a href="smtpd.8.html">smtpd(8)</a>, Postfix SMTP server 183 <a href="cleanup.8.html">cleanup(8)</a>, enqueue Postfix message 184 <a href="postconf.5.html">postconf(5)</a>, configuration parameters 185 syslogd(5), system logging 186 187<b>README FILES</b> 188 <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a>, address verification howto 189 190<b>LICENSE</b> 191 The Secure Mailer license must be distributed with this 192 software. 193 194<b>HISTORY</b> 195 This service was introduced with Postfix version 2.1. 196 197<b>AUTHOR(S)</b> 198 Wietse Venema 199 IBM T.J. Watson Research 200 P.O. Box 704 201 Yorktown Heights, NY 10598, USA 202 203 VERIFY(8) 204</pre> </body> </html> 205