NAME

flow-filter — Filter flows.

SYNOPSIS

flow-filter [-hko] [-a src_as_filter] [-A dst_as_filter] [-b big|little] [-C comment] [-D dstaddr_filter_name] [-d debug_level] [-e exaddr_filter] [-f acl_fname] [-i input_filter] [-I output_filter] [-p srcport_filter] [-P dstport_filter] [-r ipprot_filter] [-S srcaddr_filter_name] [-t tos_filter] [-T tcp_flags_filter] [-x nexthop_filter_name] [-z z_level]

DESCRIPTION

The flow-filter utility will filter flows based on user selectable criteria. The IP address filters are defined in flow.acl or by the filename specified by -f.

Other filters such as input interface and ports are defined on the command line. These filters accept range and negation operators, ie -i1-15 for input interfaces 1 through 15 or -i1,15 for input interfaces 1 and 15, or !1,15 for not input interfaces 1 and 15.

The syntax is kludgy and needs reworked but works for most applications.

OPTIONS

-a src_as_filter: Source AS filter, ie -a159 to permit Autonomous System 159.
-A dst_as_filter: Destination AS filter, ie -A159,3112 to permit Autonomous Systems 159 and 3112.
-b big|little: Byte order of output.
-C Comment: Add a comment.
-d debug_level: Enable debugging.
-D dstaddr_filter_name: Destination IP address filter. This is the name or number of a standard access list defined in flow.acl or the file specified by -f.
-e exaddr_filter: Exporter IP address filter. One exporter address can be filtered.
-f acl_fname: Access list filename. Defaults to flow.acl.
-h: Display help.
-i input_filter: Input interface filter, ie -i0 to permit traffic from interface 0.
-k: Keep time from input.
-I output_filter: Output interface filter, ie -I0 to permit traffic to interface 0.
-o: Logical OR instead of AND filters.
-p srcport_filter: Source port filter, ie -p80 to only permit source port 80.
-P dstport_filter: Destination port filter, ie -P80,8080 to permit destination ports 80 and 8080.
-r ipprot_filter: IP Protocol filter, ie -r6 to only permit TCP traffic.
-S srcaddr_filter_name: Source IP address filter. This is the name or number of a standard access list defined in flow.acl or the file specified by -f.
-t tos_filter: ToS bits filter. An optional mask is available which is applied to the tos field before comparing to the filter list. For example to match a tos bit pattern of 101xxxxx use 0xA0/0xE0.
-T tcp_flags_filter: TCP bits filter. An optional mask is available which is applied to the TCP flags field before comparing to the filter list. For example to match a flows with the SYN bit set use 0x2/0x2.
-x nexthop_filter_name: NextHop IP address filter. This is the name or number of a standard access list defined in flow.acl or the file specified by -f.
-z z_level: Configure compression level to z_level. 0 is disabled (no compression), 9 is highest compression.

EXAMPLES

Print all traffic with a destination port of 80.

flow-cat /flows/krc4 | flow-filter -P80 | flow-print

Print all traffic with with source IP 10.0.0.1. Populate flow.acl with
ip access-list standard badguy permit host 10.0.0.1

flow-cat /flows/krc4 | flow-filter -Sbadguy | flow-print

Report all destinations that IP 10.0.0.1 has sent traffic to. Sort by octets. Populate flow.acl with
ip access-list standard badguy permit host 10.0.0.1

flow-cat /flows/krc4 | flow-filter -Sbadguy | flow-stat -f8 -S2

BUGS

Extended access lists are not fully implemented. The command line filter syntax is a kludge.

NOTES

Use flow-nfilter.

AUTHOR

Mark Fullmer maf@splintered.net