| flow-filter(1) | General Commands Manual | flow-filter(1) |
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
SEE ALSO¶
flow-tools(1)