[Snort-users] Configuration issue, Part II

Erek Adams erek at ...577...
Mon Sep 24 06:55:16 EDT 2001

On Mon, 24 Sep 2001, John Sage wrote:

> Although I think Erek has something going with the real issue, here,
> questioning how *two* external interfaces are to work...

Well, you've really got two options running under Linux.  -i any and running
two instances of snort, one for each interface.


> ...let me say that this is *not* what I see.


> With snort 1.8.1-RELEASE build 74, and ipchains 1.3.9 (I know, I know..)
> on RHL 6.2, ipchains quite busily DENY's or ACCEPT's as appropriate, and
> snort happily logs everything, DENY'ed or not.
> Maybe if Marty or someone is lurking, they can comment on what the FAQ says:
> <snip>
> Q: Snort is behind a firewall (ipf/pf/ipchains/ipfilter) and awfully
> quiet...
> A: Your firewall rules will also block traffic to the snort processes.
> <snip>
> and how that reconciles with what I'm seeing.
> I'm running snort thus:
> snortREL -b -i ppp0 -c /usr/local/snort-1.8.1-RELEASE/snortREL.conf &
> and my snortREL.conf points at my rules files that essentially log
> everything.

Do you actually see packets with snort that should have been denied by the
firewall?  IOW, if you setup a firewall rule to deny all traffic from an
external site, say route-server.cerf.net, and then tried to send traffic from
the blocked site back into your net, does your snort box see it?  According to
everything we've seen so far, it shouldn't.  If you can, we'd love more info
on it!


Erek Adams

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