tcp blackhole and ident

[Matthew Seaman]

On Sat, Jan 31, 2004 at 07:46:39AM -0600, J.D. Bronson wrote:
> At 07:39 AM 1/31/2004, Matthew Seaman wrote:

> >Run ipfw(8) or a similar firewall and set up a rule that sends an ICMP
> >reject whenever it detects an incoming connection on port 113 as part
> >of your firewall configuration.  Eg. something like:
> >
> >    01600 reset tcp from any to me dst-port 113 setup

> Thanks...but I have quite a robust Cisco firewall in place ahead of the 
> freebsd machines...so I dont -need- to run ipfw...Hmmm...
> 
> Actually since the Cisco is dropping any packets already, I wonder if 
> 'blackhole' is simply a stupid idea in the first place...

Well, gee.  I'm sure Cisco PIX is capable of sending a 'reject' rather
than just dropping the packet.  Even so, don't dismiss running packet
filters locally on your FreeBSD boxes.  Think "defense in depth" -- or
how many things have to go wrong until there are bad consequences.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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