[Snort-users] BPF filters and Demarc

Gary Danko GDanko at ...9744...
Mon Jul 28 16:10:34 EDT 2003


I tried launching snort from the command line with and without the switch
for the BPF filter file. Here are my results.

Without:
[root at ...9745... conf]$ /usr/local/bin/snort -o -de -i eth1 -c
/usr/local/demarc/conf/snorteth1-a.conf                   Running in IDS
mode
Log directory = /var/log/snort

Initializing Network Interface eth1
OpenPcap() device eth1 network lookup:
        eth1: no IPv4 address assigned

        --== Initializing Snort ==--
Rule application order changed to Pass->Alert->Log
Initializing Output Plugins!
Decoding Ethernet on interface eth1
Initializing Preprocessors!
Initializing Plug-ins!
Parsing Rules file /usr/local/demarc/conf/snorteth1-a.conf

+++++++++++++++++++++++++++++++++++++++++++++++++++
Initializing rule chains...
No arguments to frag2 directive, setting defaults to:
    Fragment timeout: 60 seconds
    Fragment memory cap: 4194304 bytes
    Fragment min_ttl:   0
    Fragment ttl_limit: 5
    Fragment Problems: 0
    Self preservation threshold: 500
    Self preservation period: 90
    Suspend threshold: 1000
    Suspend period: 30
Stream4 config:
    Stateful inspection: ACTIVE
    Session statistics: INACTIVE
    Session timeout: 30 seconds
    Session memory cap: 8388608 bytes
    State alerts: INACTIVE
    Evasion alerts: INACTIVE
    Scan alerts: ACTIVE
    Log Flushed Streams: INACTIVE
    MinTTL: 1
    TTL Limit: 5
    Async Link: 0
    State Protection: 0
    Self preservation threshold: 50
    Self preservation period: 90
    Suspend threshold: 200
    Suspend period: 30
Stream4_reassemble config:
    Server reassembly: INACTIVE
    Client reassembly: ACTIVE
    Reassembler alerts: ACTIVE
    Ports: 21 23 25 53 80 110 111 143 513 1433
    Emergency Ports: 21 23 25 53 80 110 111 143 513 1433
http_decode arguments:
    Unicode decoding
    IIS alternate Unicode decoding
    IIS double encoding vuln
    Flip backslash to slash
    Include additional whitespace separators
    Ports to decode http on: 80
rpc_decode arguments:
    Ports to decode RPC on: 111 32771
    alert_fragments: INACTIVE
    alert_large_fragments: ACTIVE
    alert_incomplete: ACTIVE
    alert_multiple_requests: ACTIVE
telnet_decode arguments:
    Ports to decode telnet on: 21 23 25 119
database: compiled support for ( mysql )
database: configured to use mysql
database:          user = snort
database: database name = snort
database: password is set
database:          host = 10.1.30.60
database:   sensor name = ids1
database:     sensor id = 2
database: schema version = 106
database: using the "log" facility
0 Snort rules read...
0 Option Chains linked into 0 Chain Headers
0 Dynamic rules
+++++++++++++++++++++++++++++++++++++++++++++++++++

Rule application order: ->pass->activation->dynamic->alert->log

        --== Initialization Complete ==--

-*> Snort! <*-
Version 2.0.0 (Build 72)
By Martin Roesch (roesch at ...1935..., www.snort.org)


And with:
[root at ...9745... conf]$ /usr/local/bin/snort -F
/usr/local/demarc/conf/bpf-filters.conf -o -de -i eth1 -c
/usr/local/demarc/conf/snorteth1-a.conf
Running in IDS mode
Log directory = /var/log/snort

Initializing Network Interface eth1
OpenPcap() device eth1 network lookup:
        eth1: no IPv4 address assigned
ERROR: OpenPcap() FSM compilation failed:
        PCAP command: %s

Fatal Error, Quitting..


Here is the contents of my bpf filter:
[root at ...9745... conf]$ more bpf-filters.conf
!host 192.168.1.10
!host 10.2.20.20
!host 10.2.20.30




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