Hi,

I got confused over the antispoof settings. I turned on antispoof "Class
C" for a 192.168.x network and wondered where the packets went :-) Now I
understand how it works - or so I hope.

I think it would make more sense for the current antispoof capabilities
to be a per-interface setting instead of per-network. The generated
iptables rules in chain ANTISPOOF and the rules invoking the ANTISPOOF
chain do not depend on the network address anyway, and you get antispoof
rules for an interface if any network attached to it wants them.
Probably would break backward compatibility.

On the other hand, a different kind of per-network antispoof setting
might be desirable: you assign a network to an interface, and
packets with source addresses from that network arriving on the wrong
interface get dropped and optionally logged.
Might have some backward compatibility issues, too. Currently you are
allowed to define the same address range multiple times (with different
names and/or in different zones) and assign them to different
interfaces.


Finally a question regarding fragment handling: can I configure vuurmuur
to allow them? I found an option to turn logging on and
off but no option to forward them.
Is it necessary to block them all? I cannot really demonstrate an
application failing, but I remember reading about problems with windows
networking. Some clients would want to download software updates
dependending on available bandwidth and use a 2000 bytes ping packet
for measuring. This gets split into 2 fragments on almost all networks
(MTU being 1500 on ethernets). With a firewall dropping all fragments,
these clients concluded they had not enough bandwidth available and
never got any software updates.


Regards
Matthias Ferdinand

------------------------------------------------------------------------------
Own the Future-Intel® Level Up Game Demo Contest 2013
Rise to greatness in Intel's independent game demo contest.
Compete for recognition, cash, and the chance to get your game 
on Steam. $5K grand prize plus 10 genre and skill prizes. 
Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
_______________________________________________
Vuurmuur-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/vuurmuur-users

Reply via email to