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