[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Full-disclosure] DNS and NAT (was: DNS and CheckPoint)



On Fri, 11 Jul 2008 11:01:33 EDT, Thomas Cross said:

>     Thanks for testing this. A number of other readers wrote me privately
> confirming your result with linux ipchains. I'm not sure what ipchains does
> when it encounters a collision, but in general I think this is a good
> strategy. You'd have to have many thousands of simultaneous UDP
> transactions in order for randomly selected source ports to be colliding
> frequently enough for it to present a substantial problem.

Birthday paradox strikes again.

With 64K source ports, you'll have collisions over 1% of the time at only 1024
in use. With 8K in use, you're hitting collisions 12% of the time.

Attachment: pgpNIanUpdQDd.pgp
Description: PGP signature

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/