.\" yo there.
.TH TCPREPLAY 8  "12 April 1999"
.SH NAME
tcpreplay \- replay traffic from a saved tcpdump file
.SH SYNOPSIS
.na
.B tcpreplay
[
.B \-i
.I intf
] [
.B \-l
.I loop count
] [
.B \-r
.I rate
|
.B \-m
.I multiplier
]
.I file ...
.br
.ad
.SH DESCRIPTION
.LP
.I Tcpreplay
is a program for replaying network traffic saved in packet-trace files
generated using 
\fItcpdump(8)\fP's
.B \-w
flag.
.LP
The basic operation of
.I tcpreplay
is to resend all packets from its input file(s) at the speed at which
they were recorded, at some specified data \fIrate\fP, or as fast as the hardware is 
capable of.  If no
\fIrate\fP or
\fImultiplier\fP are given, 
.I tcpreplay 
will replay packets as fast as the hardware will allow.
If no
\fIfile\fP is given,
.I tcpreplay
will accept packet data from \fIstdin\fP.
.SH OPTIONS
.LP
.TP
.B \-i
Specify the interface to send packets out on.
.TP
.B \-r
Resend the packets at the \fIrate\fR specified (in Mbps).
.TP
.B \-m
Resend the packets at a \fImultiple\fR of the speed at which they were
recorded.
.TP
.B \-l
Resend the pcap file(s) \fIloop count\fR times.
.SH "SEE ALSO"
tcpdump(8)
.SH AUTHOR
Matt Undy, Anzen Computing.
.LP
The current version is available via HTTP:
.LP
.RS
.I http://www.anzen.com/research/nidsbench/
.RE
.SH BUGS
.I tcpreplay
can only send packets as fast as your machine's interface,
processor, and disk will allow.
.LP
``\fIN\fR write attempts failed from full buffers and were repeated''
does not indicate that these packets were not sent, but that the send
was retried \fIN\fR times until it succeeded.
.LP
Looping captured traffic may simulate odd conditions on a network.
For example, opening the same TCP connection multiple times may 
exhaust resources on machines tracking the connection. The 
.B \-l
flag is provided to allow faster sending on machines with greater I/O
constraints.
.LP
On BSD-based systems, kernel modifications are required to preserve
outgoing link layer source addresses. Refer to the \fIlibnet(3)\fP
documentation for more information on how to do this.
.LP
Please send bug reports to nidsbench@anzen.com.