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           conserver  [-7dDEFhinoRSuvV]  [-a  type] [-m max] [-M master] [-p port]
           [-b port] [-c cred] [-C config] [-P passwd] [-L logfile] [-O  min]  [-U


           Conserver  is  the daemon that manages remote access to system consoles
           by multiple users via the console(1) client  program  and  (optionally)
           log  the  console  output.  It can connect to consoles via local serial
           ports, Unix domain sockets, TCP sockets (for terminal servers  and  the
           like), or any external program.
           When  started,  conserver reads the file for details of
           each console.  The console type, logging  options,  serial  or  network
           parameters,  and  user  access levels are just a few of the things that
           can be specified.  Command-line  options  are  then  applied,  possibly
           overriding  settings.   Conserver categorizes consoles
           into two types: those it should actively manage, and  those  it  should
           just  know about, so it can refer clients to other conserver instances.
           If the master value of a console matches the hostname or ip address  of
           the  local machine, conserver will actively manage the console.  Other-
           wise, it's considered a ''remote'' console and managed by  a  different
           server.   Conserver  forks  a  child for each group of consoles it must
           manage and assigns each process a port number to listen on.  The  maxi-
           mum  number  of consoles managed by each child process is set using the
           -m option.  The console(1) client program communicates with the  master
           console  server  process  to find the port (and host, in a multi-server
           configuration) on which the appropriate child is listening.   Conserver
           restricts  connections from clients based on the host access section of
           its file, restricts users based on the  console  access
           lists  of the file, and authenticates users against its
           conserver.passwd(5) file.  Conserver can also  restrict  clients  using
           the  tcp-wrappers package (enabled using --with-libwrap).  This authen-
           tication is done before consulting the access list.
           When Unix domain  sockets  are  used  between  the  client  and  server
           (enabled using --with-uds), authentication checks are done on the hard-
           coded address ''''.  Automatic client redirection is also dis-
           abled  (as  if the -R option was used) since the client cannot communi-
           cate with remote servers.  The directory used to hold  the  sockets  is
           checked  to  make  sure  it's empty when the server starts.  The server
           will not remove any files in the directory itself,  just  in  case  the
           directory  is accidentally specified as ''/etc'' or some other critical
           location.  The server will do its best to remove all the  sockets  when
           it shuts down, but it could stop ungracefully (crash, ''kill -9'', etc)
           and leave files behind.  It would then be up to the admin  (or  a  cre-
           ative  startup script) to clean up the directory before the server will
           start again.
           Conserver completely controls any connection to a console.  All  escape
           sequences given by the user to console are passed to the server without
           interpretation.   The  server  recognizes  and  processes  all   escape
                     performed by SIGUSR2 are also performed.
           SIGUSR1   Try to connect to any consoles marked as down.  This can come
                     in handy if you had a terminal server (or more)  that  wasn't
                     accepting  connections  at  startup and you want conserver to
                     try to reconnect to all those downed ports.
           SIGUSR2   Close and reopen all console logfiles and, if in daemon  mode
                     (-d  option),  the  error  logfile  (see the -L option).  All
                     actions performed by SIGUSR1 are also performed.
           Consoles which have no current client connection might  produce  impor-
           tant  error messages.  With the -u option, these ''unloved'' errors are
           labeled with a machine name and output on stdout (or, in  daemon  mode,
           to the logfile).  This allows a live operator or an automated log scan-
           ner to find otherwise unseen errors by watching in a single location.
           Conserver must be run as root if it is to bind to a port under 1024  or
           if  it  must  read protected password files (like shadow passwords) for
           authentication (see conserver.passwd(5)).  Otherwise, it may be run  by
           any user, with -p used to specify a port above 1024.
           If  encryption has been built into the code (--with-openssl), encrypted
           client connections (without certificate exchanges) happen  by  default.
           To  add  certificate  exchanges,  use the -c option with the client and
           server.  For authentication of the certificates to  work,  the  signing
           certificate  must  be  properly trusted, which usually means the public
           portion is in OPENSSL_ROOT/ssl/certs (on both  the  client  and  server
           sides).   See  the  sample  self-signing certificate making script con-
           trib/maketestcerts for further clues.  To  allow  non-encrypted  client
           connections  (in  addition to encrypted client connections), use the -E


           Options may be given as separate arguments (e.g., -n -d)  or  clustered
           (e.g.,  -nd).  Options and their arguments may be separated by optional
           white space.  Option arguments containing spaces  or  other  characters
           special to the shell must be quoted.
           -7          Strip  the  high bit off of all data received, whether from
                       the console client or from the console device,  before  any
                       processing occurs.
           -atype      Set  the  default access type for incoming connections from
                       console clients: 'r' for refused  (the  default),  'a'  for
                       allowed,  or  't'  for  trusted.  This applies to hosts for
                       which no matching entry is found in the access  section  of
           -bport      Set  the  base  port for children to listen on.  Each child
                       starts looking for free ports at port and  working  upward,
                       trying a maximum number of ports equal to twice the maximum
           -D          Enable  debugging  output,  sent  to  stderr.   Multiple -D
                       options increases debug output.
           -E          If  encryption  has  been  built  into  the  code  (--with-
                       openssl),  encrypted  client connections are a requirement.
                       This  option  allows  non-encrypted  clients  (as  well  as
                       encrypted clients) to connect to consoles.
           -F          Do  not  automatically  reinitialize  failed  (unexpectedly
                       closed) consoles.  If the console is a program ('|' syntax)
                       and  it  closes  with  a  zero  exit status, the console is
                       reinitialized regardless  of  this  option.   Without  this
                       option,  a  console  is  immediately  reopened, and if that
                       fails, retried every minute until successful.  This  option
                       has no effect on the -o and -O options.
           -h          Output a brief help message.
           -i          Initiate console connections on demand (and close them when
                       not used).
           -Llogfile   Log errors and  informational  messages  to  logfile  after
                       startup  in  daemon  mode (-d).  This option does not apply
                       when not running in daemon mode.  The default  logfile  may
                       be changed at compile time using the --with-logfile option.
           -mmax       Set the maximum consoles managed per process.  The  default
                       max may be changed at compile time using the --with-maxmemb
           -Mmaster    Normally, this allows conserver to bind to a particular  IP
                       address  (like '') instead of all interfaces.  The
                       default is to bind to all addresses.  However,  if  --with-
                       uds   was   used   to   enable   Unix  domain  sockets  for
                       client/server communication, this points conserver  to  the
                       directory  where  it should store the sockets.  The default
                       master directory (''/tmp/conserver'')  may  be  changed  at
                       compile time using the --with-uds option.
           -n          Obsolete (now a no-op); see -u.
           -o          Normally,  a client connecting to a ''downed'' console does
                       just that.  Using this option, the  server  will  automati-
                       cally  attempt  to open (''bring up'') the console when the
                       client connects.
           -Omin       Enable  periodic  attempts  (every  min  minutes)  to  open
                       (''bring  up'')  all  downed consoles (similar to sending a
                       SIGUSR1).  Without this option, or if min is zero, no peri-
                       odic attempts occur.
                       informative message to the user.
           -S          Do  not run the server, just perform a syntax check of con-
                       figuration file and exit with a non-zero value if there  is
                       an  error.   Using more than one -S will cause conserver to
                       output various information about each console in  5  colon-
                       separated fields, enclosed in curly-braces.  The philosophy
                       behind the output is to provide information to allow exter-
                       nal detection of multiple consoles access the same physical
                       port.  Since this is highly environment-specific, conserver
                       cannot do the check internally.
                       name     The name of the console.
                       master   The  hostname of the master conserver host for the
                       aliases  The console aliases in a comma-separated list.
                       type     The type of console.  Values will be a '/'  for  a
                                local  device, '|' for a command, '!' for a remote
                                port, '%' for a Unix domain socket, and '#' for  a
                                noop console.
                       details  Multiple  values are comma-separated and depend on
                                the type of the console.  Local devices will  have
                                the  values  of the device file and baud rate/par-
                                ity.  Commands will have string to invoke.  Remote
                                ports  will have the values of the remote hostname
                                and port number.  Unix domain  sockets  will  have
                                the  path  to the socket.  Noop consoles will have
           -u          Send unloved console output to conserver's  stdout  (which,
                       in  daemon  mode,  is  redirected  to  the  logfile).  This
                       applies to all consoles to which no user is attached, inde-
                       pendent  of  whether  logging  of  individual  consoles  is
                       enabled via entries.
           -Ulogfile   Copy all console data to the ''unified'' logfile.  The out-
                       put  is  the  same  as the -u output, but all consoles, not
                       just those without a user, are logged.  Each line of output
                       is  prefixed  with the console name.  If a user is attached
                       read/write, a '*' is appended to the console name, to allow
                       log  watching  utilites to ignore potential user-introduced
           -v          Echo the configuration as it is being read (be verbose).
           -V          Output the version number and  settings  of  the  conserver
                       program and then exit.
           dren differ.  The master process gives the client access to global com-
           mands,  and  the  child provides commands for interacting with the con-
           soles it manages.  The ''help'' command, in both cases, will provide  a
           complete list of commands and a short description of what they do.
           The  second,  character-based,  style  of  interaction  occurs when the
           client issues the ''call'' command with a child process.  This  command
           connects the client to a console and, at that point, relays all traffic
           between the client and the console.  There  is  no  more  command-based
           interaction between the client and the server, any interaction with the
           server is done with the default escape sequence.
           This  is,  by  no  means,  a  complete  description   of   the   entire
           client/server  interaction.   It  is,  however,  a brief explanation in
           order to give a idea of what the program does.  See the  PROTOCOL  file
           in the distribution for further details.


           The  following default file locations may be overridden at compile time
           or by the command-line options described above.  Run  conserver  -V  to
           see the defaults set at compile time.
           /etc/        description  of  console  terminal  lines  and
                                    client   host   access   levels;   see    con-
           /etc/conserver.passwd    users  allowed  to  access  consoles; see con-
           /var/run/   the master conserver process ID
           /var/log/conserver       log of errors and informational messages
           /tmp/conserver           directory to  hold  Unix  domain  sockets  (if
           Additionally, output from individual consoles may be logged to separate
           files specified in


           I'm sure there are bugs, I just don't know where they are.  Please  let
           me know if you find any.


           Thomas A. Fine, Ohio State Computer Science
           Kevin S Braunsdorf, Purdue University Computing Center
           Bryan Stansell,


           console(1),, conserver.passwd(5)

    conserver-8.1.18 2006/12/31 CONSERVER(8)


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