PROXYMAP(8)                                           PROXYMAP(8)

NAME
       proxymap - Postfix lookup table proxy server

SYNOPSIS
       proxymap [generic Postfix daemon options]

DESCRIPTION
       The  proxymap  server provides read-only table lookup ser-
       vice to Postfix client processes. The purpose of the  ser-
       vice is:

       o      To  overcome  chroot  restrictions.  For example, a
              chrooted SMTP server needs  access  to  the  system
              passwd  file  in order to reject mail for non-exis-
              tent local addresses, but it is  not  practical  to
              maintain  a  copy  of the passwd file in the chroot
              jail.  The solution:

              local_recipient_maps =
                  proxy:unix:passwd.byname $alias_maps

       o      To consolidate the number of open lookup tables  by
              sharing  one  open  table among multiple processes.
              For example, making mysql  connections  from  every
              Postfix daemon process results in "too many connec-
              tions" errors. The solution:

              virtual_alias_maps =
                  proxy:mysql:/etc/postfix/virtual_alias.cf

              The total number of connections is limited  by  the
              number of proxymap server processes.

       The proxymap server implements the following requests:

       PROXY_REQ_OPEN maptype:mapname flags
              Open  the table with type maptype and name mapname,
              as controlled by flags.  The reply is  the  request
              completion  status  code  (below)  and the map type
              dependent flags.

       PROXY_REQ_LOOKUP maptype:mapname flags key
              Look up the data stored under  the  requested  key.
              The  reply  is  the  request completion status code
              (below) and the  lookup  result  value.   The  map-
              type:mapname  and  flags  are  the same as with the
              PROXY_REQ_OPEN request.

       There is no  close  command,  nor  are  tables  implicitly
       closed  when  a client disconnects. One of the purposes of
       the proxymap server is  to  share  tables  among  multiple
       client processes.

       The request completion status code is one of:

       PROXY_STAT_OK
              The  specified  table  was opened, or the requested
              entry was found.

       PROXY_STAT_NOKEY
              The requested table entry was not found.

       PROXY_STAT_BAD
              The request was  rejected  (bad  request  parameter
              value).

       PROXY_STAT_RETRY
              The lookup request could not be completed.

       PROXY_STAT_DENY
              The specified table was not approved for access via
              the proxymap service.

SERVER PROCESS MANAGEMENT
       The proxymap servers run under control by the Postfix mas-
       ter  server.  Each server can handle multiple simultaneous
       connections.  When all servers are  busy  while  a  client
       connects,  the  master  creates a new proxymap server pro-
       cess, provided that the proxymap server process  limit  is
       not exceeded.  Each proxymap server terminates after serv-
       ing at least $max_use clients or after  $max_idle  seconds
       of idle time.

SECURITY
       The  proxymap  server  opens only tables that are approved
       via the proxy_read_maps configuration parameter, does  not
       talk  to  users,  and  can  run  at  fixed  low privilege,
       chrooted or not.  However,  running  the  proxymap  server
       chrooted  severely  limits  usability, because it can open
       only chrooted tables.

       The proxymap server is not a trusted daemon  process,  and
       must  not be used to look up sensitive information such as
       user or group IDs, mailbox file/directory names or  exter-
       nal commands.

DIAGNOSTICS
       Problems and transactions are logged to syslogd(8).

BUGS
       The  proxymap server provides service to multiple clients,
       and must therefore not be used for tables that have  high-
       latency lookups.

CONFIGURATION PARAMETERS
       The  following  main.cf parameters are especially relevant
       to this program. Use the postfix reload  command  after  a
       configuration change.

       proxy_read_maps
              A  list  of  zero or more parameter values that may
              contain references to Postfix lookup  tables.  Only
              table   references   that  begin  with  proxy:  are
              approved for  read-only  access  via  the  proxymap
              server.

SEE ALSO
       dict_proxy(3) proxy map client

LICENSE
       The  Secure  Mailer  license must be distributed with this
       software.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

                                                      PROXYMAP(8)