.\" $OpenBSD: pflow.4,v 1.12 2012/08/22 18:22:42 jmc Exp $ .\" .\" Copyright (c) 2008 Henning Brauer .\" Copyright (c) 2008 Joerg Goltermann .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .Dd $Mdocdate: August 22 2012 $ .Dt PFLOW 4 .Os .Sh NAME .Nm pflow .Nd kernel interface for pflow data export .Sh SYNOPSIS .Cd "pseudo-device pflow" .Sh DESCRIPTION The .Nm interface is a pseudo-device which exports .Nm accounting data from the kernel using .Xr udp 4 packets. .Nm is compatible with netflow version 5, 9, and IPFIX (10). The data is extracted from the .Xr pf 4 state table. .Pp Multiple .Nm interfaces can be created at runtime using the .Ic ifconfig pflow Ns Ar N Ic create command. Each interface must be configured with a flow receiver IP address and port number. .Pp Only states created by a rule marked with the .Ar pflow keyword are exported by the .Nm interface. .Pp The .Nm interface will attempt to export multiple .Nm records in one UDP packet, but will not hold a record for longer than 30 seconds. The packet size and thus the maximum number of flows is controlled by the .Cm mtu parameter of .Xr ifconfig 8 . .Pp Each packet seen on this interface has one header and a variable number of flows. The header indicates the version of the protocol, number of flows in the packet, a unique sequence number, system time, and an engine ID and type. Header and flow structs are defined in .Aq Pa net/if_pflow.h . .Pp There is a one-to-one correspondence between packets seen by .Xr bpf 4 on the .Nm interface and packets sent out to the flow receiver. That is, a packet with 30 flows on .Nm means that the same 30 flows were sent out to the receiver. .Pp The .Nm source and destination addresses are controlled by .Xr ifconfig 8 . .Cm flowsrc is the sender IP address of the UDP packet which can be used to identify the source of the data on the .Nm collector. .Cm flowdst defines the collector IP address and the port. The .Cm flowdst IP address and port must be defined to enable the export of flows. .Pp For example, the following command sets 10.0.0.1 as the source and 10.0.0.2:1234 as destination: .Bd -literal -offset indent # ifconfig pflow0 flowsrc 10.0.0.1 flowdst 10.0.0.2:1234 .Ed .Pp The protocol is set to IPFIX with the following command: .Bd -literal -offset indent # ifconfig pflow0 pflowproto 10 .Ed .Sh SEE ALSO .Xr netintro 4 , .Xr pf 4 , .Xr udp 4 , .Xr pf.conf 5 , .Xr ifconfig 8 , .Xr tcpdump 8 .Rs .%A B. Claise .%D October 2004 .%R RFC 3954 .%T Cisco Systems NetFlow Services Export Version 9 .Re .Rs .%A B. Claise .%D January 2008 .%R RFC 5101 .%T "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information" .Re .Sh HISTORY The .Nm device first appeared in .Ox 4.5 . .Sh BUGS The IPFIX implementation is incomplete: The required transport protocol SCTP is not supported. Transport over TCP and DTLS protected flow export is also not supported.