[newbie] How do I bring eth0 down?

[Eric L. Damron]

I have a Linux server that I use for IP Masq.   I wish to bring the ethernet
card to the outside down before lowering my firewall to do work on the
server.  (I have has a LOT of attacks.)

I would just unplug the cable modem but when I do that there are a lot of
time out problems (delays)  I was hoping that I could avoid these by taking
the eth0 card off-line.  (It may not help but It's worth a try.)

Can someone tell me how to bring this card down (and back up.)  without
rebooting the server?

Thanks