tcpserver(1)

NAME

   tcpserver - accept incoming TCP connections

SYNOPSIS

   tcpserver [ -146jpPhHrRoOdDqQv ] [ -climit ] [ -xrules.cdb ] [ -Bbanner
   ] [ -ggid ] [ -uuid ] [ -bbacklog ] [ -llocalname ]  [  -ttimeout  ]  [
   -Iinterface ] host port program [ arg ...  ]

DESCRIPTION

   tcpserver waits for connections from TCP clients.  For each connection,
   it runs program with the given arguments,  with  descriptor  0  reading
   from the network and descriptor 1 writing to the network.

   The  server's  address  is  given  by  host  and  port.  host can be 0,
   allowing connections  from  any  host;  or  a  particular  IP  address,
   allowing  connections  only  to  that address; or a host name, allowing
   connections to the first IP address for  that  host.   port  may  be  a
   numeric  port  number  or  a  port  name.  If port is 0, tcpserver will
   choose a free port.

   tcpserver sets up several environment variables, as described  in  tcp-
   environ(5).

   tcpserver exits when it receives SIGTERM.

OPTIONS

   -climit
          Do  not  handle  more  than  limit simultaneous connections.  If
          there are limit simultaneous copies of  program  running,  defer
          acceptance  of  a new connection until one copy finishes.  limit
          must be a positive integer.  Default: 40.

   -xrules.cdb
          Follow the rules compiled into  rules.cdb  by  tcprules.   These
          rules  may  specify  setting  environment variables or rejecting
          connections from bad sources.

          tcpserver does not read rules.cdb into  memory;  you  can  rerun
          tcprules to change tcpserver's behavior on the fly.

   -Bbanner
          Write banner to the network immediately after each connection is
          made.  tcpserver writes banner before looking up  TCPREMOTEHOST,
          before looking up TCPREMOTEINFO, and before checking rules.cdb.

          This  feature  can  be used to reduce latency in protocols where
          the client waits for a greeting from the server.

   -ggid  Switch group ID to gid after preparing to  receive  connections.
          gid must be a positive integer.

   -uuid  Switch  user  ID  to uid after preparing to receive connections.
          uid must be a positive integer.

   -1     After preparing to receive connections,  print  the  local  port
          number to standard output.

   -4     Fall  back  to  IPv4  sockets.  This is necessary for terminally
          broken systems like OpenBSD which  will  not  let  IPv6  sockets
          connect to V4-mapped IPv6 addresses.  Please note that this also
          applies to DNS lookups, so you will have to use an DNS  resolver
          with an IPv6 address to accept IPv6 connections.  Use DNSCACHEIP
          to set the DNS resolver IP dynamically.

   -6     Force IPv6 mode in UCSPI environment variables,  even  for  IPv4
          connections.   This  will set $PROTO to TCP6 and put IPv4-mapped
          IPv6 addresses in TCPLOCALIP and TCPREMOTEIP.

   -Iinterface
          Bind to the network interface interface ("eth0"  on  Linux,  for
          example).   This  is only defined and needed for IPv6 link-local
          addresses.

   -bbacklog
          Allow up to backlog simultaneous  SYN_RECEIVEDs.   Default:  20.
          On  some  systems,  backlog  is  silently  limited  to  5.   See
          listen(2) for more details.

   -o     Leave IP options alone.  If the client is sending packets  along
          an IP source route, send packets back along the same route.

   -O     (Default.)   Kill  IP  options.   A  client can still use source
          routing to connect and to send data, but packets  will  be  sent
          back along the default route.

   -d     (Default.)   Delay  sending  data  for  a  fraction  of a second
          whenever the remote host is responding slowly,  to  make  better
          use of the network.

   -D     Never   delay   sending   data;  enable  TCP_NODELAY.   This  is
          appropriate for interactive connections.

   -q     Quiet.  Do not print any messages.

   -Q     (Default.)  Print error messages.

   -v     Verbose.  Print all available messages.

DATA-GATHERING OPTIONS

   -p     Paranoid.  After looking up the remote host name, look up the IP
          addresses  for  that  name,  and  make  sure one of them matches
          TCPREMOTEIP.  If none of them do, unset TCPREMOTEHOST.

   -P     (Default.)  Not paranoid.

   -h     (Default.)  Look up the remote host name and set TCPREMOTEHOST.

   -H     Do not look up the remote host name.

   -llocalname
          Do  not  look  up  the  local  host  name;  use  localname   for
          TCPLOCALHOST.

   -r     (Default.)   Attempt  to  obtain  TCPREMOTEINFO  from the remote
          host.

   -R     Do not attempt to obtain TCPREMOTEINFO from the remote host.

   -ttimeout
          Give up on the TCPREMOTEINFO connection  attempt  after  timeout
          seconds. Default: 26.

SEE ALSO

   argv0(1),  fixcr(1), recordio(1), tcpclient(1), tcprules(1), listen(2),
   tcp-environ(5)

                                                              tcpserver(1)

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Free and Open Source Software