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Enhancing Network Management with Cisco Data

Enhancing Network Management with Cisco Data. Brian Borowski – brianb@uwo.ca Ed Gibson – egibson@uwo.ca. Water’s Hardware. Debian Stable Release 2.4 Kernel Dual P3 @1Gig CPU’s 1.5 Gig RAM Onboard IDE - (2) 60 Gig IDE on Channel 0 (1) CDROM on Channel 1

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Enhancing Network Management with Cisco Data

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  1. Enhancing Network Management with Cisco Data Brian Borowski – brianb@uwo.ca Ed Gibson – egibson@uwo.ca

  2. Water’s Hardware • Debian Stable Release 2.4 Kernel • Dual P3 @1Gig CPU’s • 1.5 Gig RAM • Onboard IDE - • (2) 60 Gig IDE on Channel 0 • (1) CDROM on Channel 1 • Promise PD-2067 PCI - IDE Interface Card • (2) 60 Gig IDE on Channel 0 • (2) 60 Gig IDE on Channel 1 • Total of 360 Gig IDE Drive Space

  3. Water’s Partitions • 60 Gig - /, /usr • 60 Gig - /usr1 • 120 Gig (linear) - /nf1 {gate1, gate2, hse} • 120 Gig (linear) - /nf2 {nsc cat, uc cat} • /nf1 & /nf2 maintained at 90% capacity • gate2 - 65 days • hse - 60 days • cat's - 40 days

  4. NetFlow Versions

  5. Version 1 • Source Interface - SNMP Index of input interface • Source IP Address • Destination Interface - SNMP Index of output interface • Destination IP Address • Protocol - IP protocol type • (i.e, ICMP = 1, TCP = 6; UDP = 17) • Source Port - TCP/UDP source port number or equivalent • Destination Port - TCP/UDP destination port number or equivalent • Packets - Packets in the flow • Octets - Total number of Layer 3 bytes in the packets of the flow • Start Time - Unix time • Lifetime - flight time of the flow

  6. Netflow Toolkit • Utilize a netflow "toolkit" available at • http://www.splintered.net/sw/flow-tools/ • We have made some modifications • flow-capture • data collector - receives data from router • one instance per source (unique udp port) • we currently have 7 instances • zip compresses data in 16 blocks (4:1 compression) • one file per hour named rawflow.mm-dd-yyyy.hh • files >2GB required later kernel and current fileutils glibc, bash, ETC. • busy periods ~ 4-5GB/hr • custom -> filename format

  7. flow-print • Decompress and Display Data • Number of output formats • 0 short format • Sif SrcIPaddress Dif DstIPaddress Pr SrcP DstP Pkts Octets • 1 long format • Sif SrcIPaddress DIF DstIPaddress Pr SrcP DstP Pkts Octets StartTime EndTime Active B/Pk Ts Fl R1 CS MC • 6 custom format • Sif SrcIPaddress DIF DstIPaddress Pr SrcP DstP Pkts Octets start_time lifetime • generally used as a piped filter • cat ~/gate1flows/rawflow.05-14-2004.10 | flow-print -f6 | more • custom -> format type 6 (Unix time format) • custom -> display ports and protocols in decimal

  8. flow-stat • Library of predefined reports • Command Line Parameters of Interest • -P use percents instead of counters • -Sn sort descending on field n • -sn sort ascending on field n • -fn format n

  9. flow-stat(cont’d)) • 0 Overall Summary • 1 Average packet size distribution • 2 Packets per flow distribution • 3 Octets per flow distribution • 4 Bandwidth per flow distribution • 5 UDP/TCP destination port • 6 UDP/TCP source port • 7 UDP/TCP port • 8 Destination IP • 9 Source IP • 10 Source/Destination IP • 11 Source or Destination IP • 12 IP protocol • ……..

  10. flow-filter • Utility to filter traffic • Uses “kludge” of Cisco ACL format to filter IP’s (defaults file flow.acl) • Command parameters links to ACL reference • e.g. more flow.acl ip access-list standard uwoweb permit 129.100.2.71 ip access-list standard cuda permit host 129.100.1.101

  11. flow-filter (cont’d) • $ flow-filter -h Usage: flow-filter [-hko] [-a src_as_filter] [-A dst_as_filter] [-b big|little] [-C comment] [-D dstaddr_filter_name] [-d debug_level] [-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]

  12. Flow-Cat • Facilitates the concatenation of multiple flow files into a single pipe stream. • e.g. flow-cat rawflow.05-14-2004.* | flow-print -f6 | {some utility} • Other tools included in this toolkit but are beyond the scope of this presentation.

  13. flow-filter • clunky & limiting • flatten data with flow-print then process • Unix piping • grep, awk, sort • perl one liners • perl -ne '@a=split(“ “,$_);if(($a[4]==6)&&($a[6]==53)){print $_}'

  14. toolbox of scripts to perform repetitive functions • slice - pull particular time sections out of a particular day • eg. slice gate1 3 11 12 13 • flowcleaver - filter netflow output for a particular value or range in a specified column • eg. … | flow-print –f6 | flowcleaver –sip 129.100.87 | … • l3srcsum - total and index (flow,packet,octet) input stream by IP source • l3destsum - total and index (flow,packet,octet) input stream by IP destination • l4srcsum - total and index (flow,packet,octet) input stream by destination port • l4destsum - total and index (flow,packet,octet) input stream by source port • timefill – convert from Unix time to calendar time

  15. Identify Traffic Anomalies • Top N analysis • By octet • By conversations • By port • Focus analysis on anomalies • Identified by MRTG • Syslog • Netflow • IDP … • Scanner detection & BOTs

  16. Security Incident Verification • Complaint received associated with network activity two weeks ago • Netflow can verify conversation took place • What ports involved (web,smtp,IRC) • Irrefutable second source of transaction verification

  17. Protocol Distribution • Application analysis of network traffic • Percentage of Web Traffic • Locate ftp servers • Tracking BOT communication channels • Virus Infection Detection

  18. Traffic Distribution • What networks/users are hogging the Internet Pipe? • What hosts are seeing significant inbound traffic requests • Are there outside hosts dominating your outbound traffic?

  19. NetFlow Uses Access Distribution Core Distribution Access Network Layer • Attack Mitigation • User (IP) monitoring • Application monitoring • Billing • Chargeback • AS Peer Monitoring • Traffic Engineering • Traffic Analysis • Billing • Chargeback • AS Peer Monitoring • Attack Mitigation • User (IP) monitoring • Application monitoring Applications • Aggregation Schemes (v8) • “show ip cache flow” command • Arbor Networks • NetFlow MPLS Egress Accounting • BGP Next-hop (v9) • Multicast NetFlow (v9) • MPLS Aware NetFlow (v9) • BGP Next-hop (v9) • Sampled NetFlow • NetFlow MPLS Egress Accounting • BGP Next-hop (v9) • Multicast NetFlow (v9) • Aggregation Schemes (v8) • “show ip cache flow” command • Arbor Networks NetFlow Features

  20. Futures • …… • brianb@uwo.ca • egibson@uwo.ca

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