On Tue, 30 Jul 2002, Vladimir I. wrote:

> [EMAIL PROTECTED] wrote about "Re: [leaf-user] traceroute through Bering 
>firewall":
> 
> > >Why, is there a specific danger to allowing ICMP packets from your internal
> > 
> > >network to the firewall box?
> > 
> > 
> > There are some hacks based on ICMP like the icmp redirect message.
> > So is there a specific danger to allow this from your internal network?
> > I don't know depends on how much you trust the people on your internal network
> > I suppose.
> 
> Be careful when you're blocking ICMP. It breaks Path MTU 
> discovery.
> 

The assertion in an earlier post that Bering blocks all ICMP except type 8
was FUD.  By default, Shorewall still allows a sane set of ICMP packet
types to pass when the policy is DROP or REJECT.

-Tom
-- 
Tom Eastep    \ Shorewall - iptables made easy
AIM: tmeastep  \ http://www.shorewall.net
ICQ: #60745924  \ [EMAIL PROTECTED]



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