IP Masq On/Off on a running kernel

[Andrew Clark <andrew@capital.net.au>]

I know that you can turn IP forwarding on and off on a running 
kernel with something like:

echo 0 > /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/ip_forward

I was wondering if the same was possible with IP Masq?

Also, is there a library for tftp clients?  All I need to do is 
send a file to a server and be able to pull a file from a server 
(That's about all it can do isn't it?)

Regards,
	Andrew Clark

Please CC replies to this post to me, I'm not on the list.