dovecot/templates/default/conf.d/20-pop3.conf.erb

##
## POP3 specific settings
##

protocol pop3 {
  # Don't try to set mails non-recent or seen with POP3 sessions. This is
  # mostly intended to reduce disk I/O. With maildir it doesn't move files
  # from new/ to cur/, with mbox it doesn't write Status-header.
  #pop3_no_flag_updates = no

  # Support LAST command which exists in old POP3 specs, but has been removed
  # from new ones. Some clients still wish to use this though. Enabling this
  # makes RSET command clear all \Seen flags from messages.
  #pop3_enable_last = no

  # If mail has X-UIDL header, use it as the mail's UIDL.
  #pop3_reuse_xuidl = no

  # Keep the mailbox locked for the entire POP3 session.
  #pop3_lock_session = no

  # POP3 requires message sizes to be listed as if they had CR+LF linefeeds.
  # Many POP3 servers violate this by returning the sizes with LF linefeeds,
  # because it's faster to get. When this setting is enabled, Dovecot still
  # tries to do the right thing first, but if that requires opening the
  # message, it fallbacks to the easier (but incorrect) size.
  #pop3_fast_size_lookups = no

  # POP3 UIDL (unique mail identifier) format to use. You can use following
  # variables, along with the variable modifiers described in
  # doc/wiki/Variables.txt (e.g. %Uf for the filename in uppercase)
  #
  #  %v - Mailbox's IMAP UIDVALIDITY
  #  %u - Mail's IMAP UID
  #  %m - MD5 sum of the mailbox headers in hex (mbox only)
  #  %f - filename (maildir only)
  #  %g - Mail's GUID
  #
  # If you want UIDL compatibility with other POP3 servers, use:
  #  UW's ipop3d         : %08Xv%08Xu
  #  Courier             : %f or %v-%u (both might be used simultaneosly)
  #  Cyrus (<= 2.1.3)    : %u
  #  Cyrus (>= 2.1.4)    : %v.%u
  #  Dovecot v0.99.x     : %v.%u
  #  tpop3d              : %Mf
  #
  # Note that Outlook 2003 seems to have problems with %v.%u format which was
  # Dovecot's default, so if you're building a new server it would be a good
  # idea to change this. %08Xu%08Xv should be pretty fail-safe.
  #
  #pop3_uidl_format = %08Xu%08Xv

  # Permanently save UIDLs sent to POP3 clients, so pop3_uidl_format changes
  # won't change those UIDLs. Currently this works only with Maildir.
  #pop3_save_uidl = no

  # POP3 logout format string:
  #  %i - total number of bytes read from client
  #  %o - total number of bytes sent to client
  #  %t - number of TOP commands
  #  %p - number of bytes sent to client as a result of TOP command
  #  %r - number of RETR commands
  #  %b - number of bytes sent to client as a result of RETR command
  #  %d - number of deleted messages
  #  %m - number of messages (before deletion)
  #  %s - mailbox size in bytes (before deletion)
  #  %u - old/new UIDL hash. may help finding out if UIDLs changed unexpectedly
  #pop3_logout_format = top=%t/%p, retr=%r/%b, del=%d/%m, size=%s

  # Maximum number of POP3 connections allowed for a user from each IP address.
  # NOTE: The username is compared case-sensitively.
  #mail_max_userip_connections = 10

  # Space separated list of plugins to load (default is global mail_plugins).
  #mail_plugins = $mail_plugins

  # Workarounds for various client bugs:
  #   outlook-no-nuls:
  #     Outlook and Outlook Express hang if mails contain NUL characters.
  #     This setting replaces them with 0x80 character.
  #   oe-ns-eoh:
  #     Outlook Express and Netscape Mail breaks if end of headers-line is
  #     missing. This option simply sends it if it's missing.
  # The list is space-separated.
  #pop3_client_workarounds = 
}