• Introduction to IMAP
• Introduction to Cyrus IMAP
• Quick Installation
• Configuration
• Example Installations
• Conclusion

What is IMAP?

• Internet Mail Layers
• MTA - Mail Transfer Agent
• MUA - Mail User Agent
• MP[AL] - Mail Presentation Agent/Layer
• Internet Standard for Mail Access
• Supported By Most MUAs

• On-line
• Access Mail Anywhere
• Stored on Server, Not Client
• Persistent Message Flags
• Concurrent Access
• Disconnected Access
• Multiple Folders on Server
• Shared Mailboxes
• Store/Post Message (If MUA Supports)

Background

• Developed at Carnegie Mellon, to Meet University Needs
• Began In 1994 As Part of Andrew Distributed Computing System
• Became Free Software Around 2000
• BSD-ish License

• Fast and Scalable
• Efficient Storage
• Shared Mailboxes
• Access Control Lists
• Server-side Mail Filtering with Sieve
• Duplicate Suppression
• Indexed Server-side Searching with Squatter
• SSL/TLS Support
• Direct Mailbox Delivery with Address Extension

• Virtual Hosting
• "Blackbox" Server
• Flexible Authentication with Cyrus SASL
• Message Expiration with ipurge
• Real Quotas
• Single-Instance Store
• Partitioned Storage
• POP3 and NNTP Servers
• Clusterable w/Murder

• Flexible Authentication Can Also Be Complex
• Database Problems With Older Berkeley DB Versions
• Was Not Free Software
• More Complicated Management
• Difficult Migration
• Documentation Spotty
• Percieved Problems
• Mail Storage is Opaque
• Per-user Spam Scanning Is Tough
• Databases Cannot be SQL Server

Fedora Core 3

• FC3 has Cyrus SASL and Cyrus IMAP Configured For "Typical" Use
• Remove UW-IMAP
• Install Packages

# yum install postfix cyrus-imapd cyrus-imapd-utils \
    perl-Cyrus cyrus-sasl cyrus-sasl-plain \
    perl-Term-ReadLine-Gnu
                

• Start saslauthd and imapd

# /sbin/service saslauthd start
# /sbin/service cyrus-imapd start
                

• Set Password For Admin User cyrus
• Create Mailboxes With Admin Tool cyradm

$  cyradm --user cyrus localhost
IMAP Password: 
localhost> createmailbox user.wcooley
localhost> listmailbox user.wcooley
user.wcooley (\HasNoChildren)  
localhost> listaclmailbox user.wcooley
wcooley lrswipcda
localhost> listquotaroot user.wcooley

• Configure and Start Postfix

# alternatives --set mta /usr/sbin/sendmail.postfix 
# postconf -e  mailbox_transport=\
lmtp:unix:/var/lib/imap/socket/lmtp
# /sbin/service sendmail stop
# /sbin/service postfix start

• Now Have a Live Cyrus IMAP Server!

• cyradm is Command-Line Management Tool
• /etc/cyrus.conf Start-up, Super-server, Scheduling, Like init, inetd, cron
• /etc/imapd.conf Holds Configuration Parameters
• Several Other Test and Data Store Utilities
• Deleting Mailboxes

localhost> cm user.wcooley.test
localhost> dm user.wcooley.test
deletemailbox: Permission denied
localhost> sam user.wcooley.test cyrus c
localhost> dm user.wcooley.test

• Use cyradm To Manage
• deleteacl
• setacl
• listacl


• l: Lookup (visible to LIST/LSUB/UNSEEN)
• r: Read (SELECT, CHECK, FETCH, PARTIAL, SEARCH, COPY source)
• s: Seen (STORE \SEEN)

• w: Write flags other than \SEEN and \DELETED
• i: Insert (APPEND, COPY destination)
• p: Post (send mail to mailbox)
• c: Create and Delete mailbox (CREATE new sub-mailboxes, RENAME or DELETE mailbox)
• d: Delete (STORE \DELETED, EXPUNGE)
• a: Administer (SETACL)

• Write a Sieve Script

require [ "fileinto", "imapflags" ];
if header :contains "From" [ "billg@microsoft.com",
        "robinson-west.com" ] {
    addflag "\\Seen"; 
}
elsif header :contains "X-BeenThere" "plug-announce" {
    fileinto "INBOX.plug.announce";
}
elsif header :contains "X-BeenThere" "plug@" {
    fileinto "INBOX.plug";
}
elsif header :contains "X-BeenThere" "plug-*@" {
    fileinto "INBOX.plug.other";
}

• Upload Script

$ sieveshell localhost
connecting to localhost
Please enter your password: 
> put sieve-script 
> ls
sieve-script 
> activate sieve-script
> ls
sieve-script  <- active script
> quit

• "+" Recipient Delimiter in Most MTAs
• Create Mailbox and Set ACL

localhost> setaclmailbox INBOX.plug \
    anonymous p
localhost> listaclmailbox INBOX.plug
anonymous p
wcooley lrswipcda

• Messages for wcooley+plug@nakedape.cc Delivered Directly to INBOX.plug

• Create Mailbox and Set ACLs

  localhost> cm shared.announcements
  localhost> lam shared.announcements
  anyone lrs
  localhost> sam shared.announcements \
      group:wcooley all
  localhost> lam shared.announcements
  group:wcooley lrswipcda
  anyone lrs
  

• Sometimes Need to Fiddle With MUAs Namespace Setting
• postuser in /etc/imapd.conf Provides Extension-based Posting
• Default "bb" (bb+shared.announcements@)
• Some MTAs Can Even Post Directly!

• Use cyradm to Setup

localhost> setquota user.wcooley 10240
quota:10240
localhost> lq user.wcooley
 STORAGE 0/10240 (0%)

• Use quotawarn or quotawarnkb in /etc/imapd.conf to Warn Users
• Use lmtp_over_quota_perm_failure to Control Whether Messages Bounce or Are Held In MTA's Queue

• Searching Large Mailboxes Is Nearly Instantaneous
• Running Once Daily Is Enough
• Messages Not Indexed Will Be Searched Directly
• Add Entry to /etc/cyrus.conf

  EVENTS {
    ...
    squatter cmd="squatter -s -r user" at=0200
    ...
  }
  

Eric Harrison, Multnomah Education Service District

• 1413 Mailboxes, 700-800 Concurrent Users
• Hardware:
• Dual 2.4GHz Xeons
• 2G RAM
• Three 36G U320 SCSI Drives, Hardware RAID5

• 9695 Mailboxes, 700-800 Concurrent Users
• Hardware:
• Single Pentium III 1GHz
• 1GB RAM
• Single 36G U160 SCSI Drive

Andrew Morgan, Oregon State University

• 3500 Accounts, 300 Concurrent Users
• 250,000 Logins Daily, 7500 Users
• Dual 2.8GHz Pentium 4
• 2GB RAM
• Fourteen 73GB 15k drives, RAID 1+0.

• Introduced IMAP and Cyrus IMAP
• Quick Installation on Fedora Core 3
• Overview of Mailbox Management, ACLs, Sieve, Quotas, Extension Delivery, Shared Mailboxes and Squatter.