Re: Linux 2.4.27 SECURITY BUG - TCP Local and REMOTE(verified) Denial of Service Attack

Florian Weimer
2004-09-21T18:32:55Z

* Herbert Xu:

> Florian Weimer <fw@deneb.enyo.de> wrote:
>>
>>>> TCP-MD5 has no effect on ICMP based attacks.,
>>>
>>> Hmm, good point. Which attacks, and what could be done about them?
>>> (other than IPsec protect all traffic between peers).
>>
>> You just filter ICMP packets, in the way RST packets are already
>> filtered (i.e. rate limit).
>
> Rate-limiting has no effect on ICMP attacks unless your limit is such
> that you're effectively dropping them all.

Yes, that's the idea. Keep in mind that all this is about traffic
destined to a router interface address, not about forwarded traffic.

> But then you get PMTU problems...

PMTU discovery is not an issue because it's turned off anyway, at
least by default.