Re: FreeBSD DDoS protection

As my response stated filter ICMP except where necessary. I can state coming from a mitigation background that there are ways to safely do it without causing any issues. However, yes, you can still filter ICMP and remain compliant with an example pf rule like:
icmp_types = "{ echoreq, unreach }"

But in real life situations under constant attacks, blocking ICMP can be a large part of keeping businesses online.

If everything was standard and attackers followed the packet/traffic specifications then going by the standard would be no problem. That's not the case and sometimes guidelines have to be situational.



-Kevin






On Feb 12, 2013, at 10:54 AM, "Norbert Aschendorff" <[email protected]> wrote:

> In fact, it's specified in RFC1122:
> 
> 
>         3.2.2.6  Echo Request/Reply: RFC-792
> 
>         Every host MUST implement an ICMP Echo server function that
>         receives Echo Requests and sends corresponding Echo Replies.
> 
> I think it implies that the implementation should actually work. :)
> 
> --Norbert
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