Provided by: ucspi-tcp_0.88-3_i386 bug


       tcpserver - accepts incoming TCP connections.


       tcpserver [ opts ] host port prog


       opts  is a series of getopt-style options.  host is one argument.  port
       is one argument.  prog consists of one or more arguments.

       tcpserver waits for connections from TCP clients. For each  connection,
       it runs prog, with descriptor 0 reading from the network and descriptor
       1  writing  to  the  network.  It  also  sets  up  several  environment

       The  server's  address  is  given by host and port.  port may be a name
       from /etc/services or a number; if it is 0,  tcpserver  will  choose  a
       free  TCP  port.   host  may be 0, allowing connections to any local IP
       address; or a dotted-decimal IP address, allowing connections  only  to
       that  address;  or  a  host  name, allowing connections to the first IP
       address for that host. Host names are fed through  qualification  using

       tcpserver exits when it receives SIGTERM.


       General options:

       -q     Quiet. Do not print error messages.

       -Q     (Default.) Print error messages.

       -v     Verbose. Print error messages and status messages.

       Connection options:

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

       -x cdb Follow the rules compiled into cdb by tcprules(1).  These  rules
              may   specify   setting   environment   variables  or  rejecting
              connections from bad  sources.  You  can  rerun  tcprules(1)  to
              change the rules while tcpserver is running.

       -X     With  -x  cdb,  allow  connections  even  if cdb does not exist.
              Normally tcpserver will drop the  connection  if  cdb  does  not

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

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

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

       -U     Same  as  -g  $GID  -u  $UID. Typically $GID and $UID are set by

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

       -b n   Allow  a backlog of approximately n TCP SYNs. On some systems, n
              is silently limited to 5. On systems supporting SYN cookies, the
              backlog is irrelevant.

       -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     Delay sending data for a  fraction  of  a  second  whenever  the
              remote host is responding slowly. This is currently the default,
              but it may not be  in  the  future;  if  you  want  it,  set  it

       -D     Never delay sending data; enable TCP_NODELAY.

       Data-gathering options:

       -h     (Default.)  Look  up  the  remote  host  name  in DNS to set the
              environment variable $TCPREMOTEHOST.

       -H     Do not  look  up  the  remote  host  name  in  DNS;  remove  the
              environment  variable  $TCPREMOTEHOST.  To avoid loops, you must
              use this option for servers on TCP port 53.

       -p     Paranoid. After looking up the remote host name in DNS, look  up
              the  IP  addresses  in  DNS  for  that host name, and remove the
              environment variable $TCPREMOTEHOST if  none  of  the  addresses
              match the client's IP address.

       -P     (Default.) Not paranoid.

       -l localname
              Do not look up the local host name in DNS; use localname for the
              environment  variable  $TCPLOCALHOST.  A   common   choice   for
              localname  is  0.  To  avoid loops, you must use this option for
              servers on TCP port 53.

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

       -R     Do not attempt to obtain $TCPREMOTEINFO from the remote host. To
              avoid loops, you must use this option for servers on  TCP  ports
              53 and 113.

       -t n   Give  up  on  the  $TCPREMOTEINFO  connection  attempt  after  n
              seconds. Default: 26.


       tcprules(1),  tcprulescheck(1),  argv0(1),   fixcrio(1),   recordio(1),
       rblsmtpd(1),  tcpclient(1),  who@(1),  date@(1),  finger@(1), http@(1),
       tcpcat(1), mconnect(1), tcp-environ(5)