Snort mailing list archives
Re: snort + iptables
From: "Senthil Prabu.S" <prabu333 () hotpop com>
Date: Fri, 26 Nov 2004 14:50:36 +0530
Hi I was wondering : If I put snort on the same machine iptables is running both will catch the same packets or frames? I think this is a waste of resources, isn't it? I know snort_inline accepts only packets from iptables, so that's OK! But what about snort? It is still using libpcap to catch the traffic,
Snort operates using libpcap.It analysis everything the network adapter driver sees before the network stack munges it. Linux IPTables, do not prevent snort from seeing a packet that is present on the network wire. Even if an inbound packet is denied by the packet filter,ie by IPTables. Snort will still see and analyze the packet if it is listening to that interface. Snort/pcap sees whatever comes out of
or goes into the network adapter. The above said holds good for only inbound trafiic.
how can I make it listen only to the traffic iptables filter?
Also Snort cannot look at the outgoing packets that are being denied by filters,since they will never reach the network adapter. Hopes this helps.... -- Senthil Prabu.SLogic is a systematic method of coming to the wrong conclusion with confidence.
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Current thread:
- snort + iptables andrea (Nov 26)
- Re: snort + iptables Senthil Prabu.S (Nov 26)