diff options
Diffstat (limited to 'usr.bin/nc/nc.1')
| -rw-r--r-- | usr.bin/nc/nc.1 | 63 |
1 files changed, 42 insertions, 21 deletions
diff --git a/usr.bin/nc/nc.1 b/usr.bin/nc/nc.1 index 1c0cd6fa482..c069c29c11b 100644 --- a/usr.bin/nc/nc.1 +++ b/usr.bin/nc/nc.1 @@ -1,4 +1,4 @@ -.\" $OpenBSD: nc.1,v 1.6 1999/06/05 01:21:34 aaron Exp $ +.\" $OpenBSD: nc.1,v 1.7 2000/03/10 19:07:22 aaron Exp $ .\" .\" Copyright (c) 1996 David Sacerdote .\" All rights reserved. @@ -50,9 +50,11 @@ The (or .Nm netcat ) utility is used for just about anything under the sun -involving TCP or UDP. It can open TCP connections, send UDP packets, +involving TCP or UDP. +It can open TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, do port scanning, and source -routing. Unlike +routing. +Unlike .Xr telnet 1 , .Nm scripts nicely, and separates error messages onto standard error instead @@ -62,11 +64,13 @@ does with some. .Pp Destination ports can be single integers, names as listed in .Xr services 5 , -or ranges. Ranges are in the form nn-mm, and several separate ports and/or +or ranges. +Ranges are in the form nn-mm, and several separate ports and/or ranges may be specified on the command line. .Pp Common uses include: -.Bl -bullet +.Pp +.Bl -bullet -offset indent -compact .It simple TCP proxies .It @@ -83,16 +87,19 @@ The options are as follows: .Bl -tag -width Ds .It Fl e Ar command Execute the specified command, using data from the network for stdin, -and sending stdout and stderr to the network. This option is only present if +and sending stdout and stderr to the network. +This option is only present if .Nm was compiled with the GAPING_SECURITY_HOLE compile time option, since it allows users to make arbitrary programs available to anyone on the network. .It Fl g Ar intermediate-host -Specifies a hop along a loose source routed path. Can be used more than -once to build a chain of hop points. +Specifies a hop along a loose source routed path. +Can be used more than once to build a chain of hop points. .It Fl G Ar pointer -Positions the "hop counter" within the list of machines in the path of -a source routed packet. Must be a multiple of 4. +Positions the +.Dq hop counter +within the list of machines in the path of a source routed packet. +Must be a multiple of 4. .It Fl i Ar seconds Specifies a delay time interval between lines of text sent and received. Also causes a delay time between connections to multiple ports. @@ -100,7 +107,8 @@ Also causes a delay time between connections to multiple ports. Is used to specify that .Nm should listen for an incoming connection, rather than initiate a -connection to a remote host. Any hostname/IP address and port arguments +connection to a remote host. +Any hostname/IP address and port arguments restrict the source of inbound connections to only that address and source port. .It Fl n @@ -108,8 +116,17 @@ Do not do DNS lookups on any of the specified addresses or hostnames, or names of port numbers from /etc/services. .It Fl o Ar filename Create a hexadecimal log of data transferred in the specified file. -Each line begins with ``<'' or ``>''. ``<'' means "from the net" and ``>'' -means "to the net". +Each line begins with +.Ql < +or +.Ql > . +.Ql < +means +.Dq from the net +and +.Ql > +means +.Dq to the net . .It Fl p Ar port Specifies the source port .Nm @@ -127,9 +144,11 @@ to bring up a dummy interface with the desired source IP address. Causes .Nm to send RFC854 DON'T and WON'T responses to RFC854 DO -and WILL requests. This makes it possible to use +and WILL requests. +This makes it possible to use .Nm -to script telnet sessions. The presence of this option can be +to script telnet sessions. +The presence of this option can be enabled or disabled as a compile-time option. .It Fl u Use UDP instead of TCP. @@ -139,9 +158,11 @@ will behave as if a connection is established until it receives an ICMP packet indicating that there is no program listening to what it sends. .It Fl v -Verbose. Cause +Verbose. +Cause .Nm -to display connection information. Using +to display connection information. +Using .Fl v more than once will cause .Nm @@ -157,9 +178,8 @@ input closes. Specifies that .Nm should just scan for listening -daemons, without sending any data to them. Diagnostic messages about refused -connections will not be -displayed unless +daemons, without sending any data to them. +Diagnostic messages about refused connections with not be displayed unless .Fl v is specified twice. .Sh EXAMPLES @@ -168,7 +188,8 @@ is specified twice. Wait for the user to type what would normally be command-line arguments in at stdin. .It Li "nc example.host 42" -Open a TCP connection to port 42 of example.host. If the connection +Open a TCP connection to port 42 of example.host. +If the connection fails, do not display any error messages, but simply exit. .It Li "nc -p 31337 example.host 42" Open a TCP connection to port 42 of example.host, and use port 31337 |