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Questions about bogon filtering [Was: Re: Firewall update (if you're filtering bogons)]



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Arjan wrote:
> The list of IPv4 Global Unicast Address Assignments got updated yesterday:
> 	http://iana.org/assignments/ipv4-address-space/
> 
> The previously unallocated prefix 197/8 has been allocated. Please
> remove it from your firewall filter if you're filtering bogons.
> 
> 

A question: Does filtering bogons really help security all that much? I
would think that about all it'd be good for would be dropping packets
with spoofed IDs - but in the case of a DDoS, where such a thing is
likely, they've accomplished their goal simply by having the packet get
across your uplink and bounce off your firewall.

I suppose it could help spare load on a server in the case of a SYN
flood directed towards one, but I would think it wouldn't be all that
hard to adjust the RNG algorithm (or counter, or whatever) to have the
spoofed IPs on the packets generated only in non-bogon space.

- --
F. Fox
Owner of Tor node "kitsune"
http://fenrisfox.livejournal.com
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