1 = Mail Integration = 2 3 To act as a part of an e-mail system, imip-agent provides a number of programs 4 that may be invoked by mail transfer agents (MTAs) upon sending or receiving 5 messages. In order to uphold portability and to minimise configuration issues, 6 these programs need only be registered as simple mail handlers or transports, 7 thus potentially supporting a wide range of MTAs. 8 9 Once imip-agent has processed a message, it may then deliver it to its 10 intended recipient. The mail storage systems that may receive messages from 11 imip-agent need only support the delivery mechanisms used by imip-agent. 12 Otherwise, few constraints should be imposed by each kind of system on the 13 other. 14 15 ######## A diagram summarising the mail transport integration. 16 17 {{{#!graphviz 18 //format=svg 19 //transform=notugly 20 digraph mail_integration { 21 node [shape=box,fontsize="13.0",fontname="Helvetica",tooltip="Mail integration"]; 22 edge [tooltip="Mail integration"]; 23 rankdir=LR; 24 25 mail [label="Incoming mail",shape=folder,style=filled,fillcolor=cyan, 26 href="../IncomingMessages"]; 27 28 subgraph { 29 rank=same; 30 personrouter [label="Person router"]; 31 resourcerouter [label="Resource router"]; 32 recipients [label="Recipient database",shape=folder]; 33 } 34 35 subgraph { 36 rank=same; 37 personhandler [label="Person handler",style=filled,fillcolor=gold]; 38 resourcehandler [label="Resource handler",style=filled,fillcolor=gold, 39 href="../Resources"]; 40 scheduling [label="Scheduling",shape=ellipse,style=filled,fillcolor=gold]; 41 freebusy [label="Free/busy",shape=folder,style=filled,fillcolor=gold, 42 href="../FreeBusyPublishing"]; 43 } 44 45 mailbox [label="Mailboxes\n(Cyrus, Dovecot, ...)",tooltip="Mailboxes", 46 href="../MailboxIntegration"]; 47 48 mail -> personrouter -> personhandler -> mailbox; 49 mail -> resourcerouter -> resourcehandler 50 51 recipients -> personrouter; 52 recipients -> resourcerouter; 53 54 personhandler -> scheduling; 55 resourcehandler -> scheduling; 56 scheduling -> freebusy; 57 } 58 }}} 59 60 ######## 61 62 == MTAs == 63 64 Currently, imip-agent supports [[http://exim.org/|Exim]] and 65 [[http://www.postfix.org/|Postfix]], although this support should be readily 66 broadened, and offers configuration resources for these supported systems so 67 as to allow imip-agent to be deployed within existing mail-sending and 68 delivery infrastructures. 69 70 {{{#!table 71 || '''Identifying Recipients''' || '''Integrating imip-agent''' || '''Notes''' 72 == 73 '''Exim''' 74 || Routers identify recipients of mail that shall be handled by imip-agent 75 || Transports invoke imip-agent programs 76 || Exim is widely deployed as the default MTA for Debian. Consequently, it is 77 .. desirable to support this software in imip-agent. 78 == 79 '''Postfix''' 80 || Virtual aliases identify recipients of mail that shall be handled by 81 .. imip-agent 82 || Transports invoke imip-agent programs 83 || Postfix is also widely deployed and is sometimes preferred by administrators. 84 }}} 85 86 Some hints on mail system configuration can be found in the [[/MTA|MTA guide]]. 87 88 == Identification of Recipients == 89 90 In principle, any mechanism supported by the MTA can be used to identify 91 recipients; imip-agent does not employ identification mechanisms of its own. 92 Thus, the task of identifying recipients is one of MTA configuration, with the 93 following mechanisms tested: 94 95 {{{#!table 96 '''Identification Mechanisms''' || '''Tested with...''' 97 == 98 [[/LDAP|LDAP]] || Exim, Postfix 99 == 100 [[/Simple|Simple (list-based identification)]] || Exim, Postfix 101 }}} 102 103 It is worth repeating that imip-agent does not try and validate users. Once 104 the MTA has decided that a recipient can actually receive a message, and once 105 that message is passed to one of the [[../AgentPrograms|agent programs]], the 106 software will process that message and record information for the recipient in 107 the [[../FilesystemUsage|filesystem structures]] for the user. 108 109 See the [[../Usage|usage guide]] for information on preparing data stores for 110 users in advance of any mail being received for them. 111 112 === The Calendar System Address === 113 114 Since imip-agent may send messages on behalf of calendar users, the address 115 it uses to do so must be recognised by the MTA. This may be done by adding 116 an entry to the `/etc/aliases` file such as the one defined in the 117 `conf/aliases.example` file: 118 119 {{{ 120 calendar: root 121 }}} 122 123 More suitable routing can be defined as desired. See the `MESSAGE_SENDER` 124 setting defined in the `config.txt` file described in the 125 [[../Configuration|configuration guide]]. 126 127 == Invoking the Agent Programs == 128 129 Regardless of identification or delivery mechanisms, the imip-agent software 130 must be integrated into the mail processing pipeline so that messages can be 131 interpreted and processed. This is done by configuring the MTA's 132 [[/Transports|transport mechanisms]]. 133 134 == Delivery == 135 136 To deliver messages to their ultimate recipients after having processed them, 137 imip-agent currently employs either local SMTP connections or 138 [[https://tools.ietf.org/html/rfc2033|LMTP]]. There is nothing in principle 139 preventing imip-agent from also supporting other common delivery mechanisms, 140 however. 141 142 {{{#!table 143 '''Delivery Mechanisms''' || '''Tested with...''' 144 == 145 [[/LocalSMTP|Local SMTP]] || Exim, Postfix 146 == 147 [[/LMTP|LMTP]] || Exim, Postfix 148 }}} 149 150 See the [[../MailboxIntegration|mailbox integration guide]] for a brief 151 overview of configuring mail storage solutions.