any experience with "flakeways"?

[Trevor Pirman]

I need to set up a machine that will act as a "flakeway", the term I
have heard used for an application that randomly drops packets or causes
timeouts for services such as DNS and routing.

I studied up on the net about this, and people talk about it, but no one
offers where to find any out of the box software.  Maybe they are
building their own "flakeway"?

What I want to do is configure a DNS server that causes requests to the
server to time out.  I set up ipfw on one machine to swallow all tcp and
udp packets to port 53, and them made this host my DNS server.  This
worked for some tests I did, but not others.  I need a more robust
solution.

Can anyone offer any advice or pointers on how to do this?   Any info
would be great.

TIA

-Trevor