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Re: [suse-security] Firewall Check


> > --> A router cannot detect which program sent the package. It can deny 
> > access to certain IP ranges and/or certain port ranges.
> Ok - this was a clear point. And what about standalone firewalls (i.E. 
> SuSE Firewall) ?
--> As pointed out already, there may be some change to guess from the 
content of the packets which application is behind. But this applies 
for SuSE Firewall as well.

> I think, to block such internet access is only possible with an 
> client-based firewall, which knows the programs and dlls which are 
> allowed to access the net ?
--> Yes. A nice one for windows is "Personal Firewall" it can display 
pop-up windows for packets that do not match any rule and you can 
restrict internet access to certain applications (they are identified 
by md5 checksums so even naming a trojan "netscape.exe" won't help).

> > The important point IMHO is to teach users not to download programs 
> > from the internet without thorough checking of the intention of the 
> > program. And of course not to click on suspicious links or open Email 
> > Attachments.
> I think the only posibility to avoid such dangers is to prevent users 
> from downloading ANY program ;-)
--> Yes, but I guess in most places this is not an option as it means 
restricting net access very much. Think about naming a file 
"program.html" and then save it as "program.exe". It would require a 
real content-check based on "magic chars" in each document that is 
retrieved from the net.


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