Retraining "IT" on networking myths (the cloud to the rescue!)
Michael Sinatra
michael at rancid.berkeley.edu
Thu Jun 9 01:54:34 UTC 2011
On 06/08/11 18:32, Jared Mauch wrote:
> MYTHS:
>
> TCP/53 is only for zone transfers ICMP is a security risk/ddos
> avenue Internal networks must be secured with NAT A firewall is the
> only way to secure the perimiter
>
> In fact for IPv6, ICMP is more important vs less. Firewalls
> frequently harm and don't block data going out. TCP/53 is needed for
> EDNS.
tcp/53 is needed when EDNS is _not_ available and DNS message size
exceeds 512 bytes. UDP fragments are (sometimes) necessary for EDNS.
So, that adds to your MYTHS section:
Fragmented packets (like ICMP) are always a security risk and DDoS vector
michael
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