-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
.
These rules may specify setting environment variables
or rejecting connections from bad sources.
You can rerun tcprules
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 exist.
-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 explicitly.
-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 host.
-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.
