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       radrelay.conf - configuration file for the FreeRADIUS server "radrelay"


       The radrelay.conf file resides in the  radius  database  directory,  by
       default  /etc/raddb.   It  defines  the  global  configuration  for the
       FreeRADIUS server, when the server is operating as "radrelay".


       For a detailed description of the file format, see "man  radiusd.conf".
       The  configuration  entries are much the same for radrelay.conf, with a
       few differences as noted here.


       Many sites run multiple radius servers; at least one  primary  and  one
       backup  server.  When the primary goes down, most NASes detect that and
       switch to the backup server.

       That will cause your accounting packets to go the the backup  server  -
       and  some  NASes  don’t  even switch back to the primary server when it
       comes back up.

       The  result  is  that  accounting  records  are  missed,   and/or   the
       administrator must jump through hoops in order to combine the different
       detail files from multiple servers. It  also  means  that  the  session
       database  ("radutmp",  used  for radwho and simultaneous use detection)
       gets out of sync.

       radrelay solves this issue by "relaying" packets  from  one  server  to
       another, so they both have the same set of accounting data.


       If the RADIUS server suddenly receives a many accounting packets, there
       may be insufficient CPU power to process them all in a  timely  manner.
       This  problem  is  especially noticable when the accounting packets are
       going to a back-end database.

       Similarly, you may have one database that tracks "live"  sessions,  and
       another   that  tracks  historical  accounting  data.   In  that  case,
       accessing the first database is fast, as it is  small.   Accessing  the
       second database many be slower, as it may contain multiple gigabytes of
       data.  In addition, writing to the first database in a timely manner is
       important,  while data may be written to the second database with a few
       minutes delay, without any harm being done.


       The radrelay.conf file  controls  the  "radrelay"  personality  of  the
       server, which can perform both of the functions above at the same time.


       First, you should configure the main radius server to log to an  extra,
       single  detail  file.   This may be done by adding an extra instance of
       the detail module to radiusd.conf:

       For example:

                   detail radrelay-detail {
                        detailfile = ${radacctdir}/radrelay/detail
                        detailperm = 0600
                        dirperm = 0755
                        locking = yes
                   accounting {

       This configuration will cause accounting packets to be  logged  to  the
       ${radacctdir}/radrelay/detail file.  This file should not be rotated by
       standard log rotation scripts, as the radrelay program  will  read  and
       rotate it.


       See  the  radrelay.conf file for detailed instructions on configuration
       entries, what they mean, and how to use them.

       To have the "radrelay" portion of the  server  read  the  above  detail
       file, configure radrelay.conf with the following section:

                   listen {
                        type = detail
                        detail = ${radacctdir}/radrelay/detail
                        max_outstanding = 100
                        identity = radrelay

       The  server  will read the accounting packets from the detail file, and
       process them just as if it had received them from the NAS.   Therefore,
       you should configure the "accounting" section of radrelay.conf to write
       the accounting records to an "sql" module, or to proxy them to  another
       RADIUS server.

       Then, start the server via the following command:

       $ radiusd -n radrelay

       The  server  should  start  up,  read  the  detail  file,  and  process
       accounting packets from it.


       The radiusd.conf file is not read at all when the server is running  as
       radrelay.  Please edit radrelay.conf.


       The  original  "radrelay" program was written by Miquel van Smoorenburg
       for the Cistron radius project,  and  ported  to  FreeRADIUS  by  Simon
       Ekstrand.   The  "radsqlrelay"  was written by Kostas Kalavras.  It was
       never released as part of an offical FreeRADIUS release, but served  as
       a basis for the design of this implementation.




       radiusd(8), radiusd.conf(5)


       Alan DeKok <>

                                  27 May 2005                 radrelay.conf(5)