Newbie DHCP question

I'm not sure I fully understand the principle behind DHCP. This is my
scenario/configuration.

I've got a small home network using a Linksys router (WRT54G) and have
my main computer connected directly into the router. Until recently, I
had the router default settings for DHCP (I had changed everything
else) but was trying the port forwarding option for some gaming. In
doing so, I was under the impression (after reading information on port
forwarding) that I had to change my setup to a static IP, so I did.

After fooling around a bit, trying different settings, and talking with
a tech at my local university, I realized that I didn't have to have a
static IP, but rather extend the "refresh time" (is that the correct
terminology?) for my DHCP. I did this and everything ran smoothly.

Curiosity (evil thing) being what it is, I decided to check my IP
address using ipconfig /all and discovered that while it did show I had
DHCP set up (complete with lease expiration times) it was still the
same original IP from the day prior. So, to verify, I shortened the
lease time in my router's settings to one minute. I wanted to see two
things: first, if it was actually changing my IP; and second, if the
change would affect my connection. So after shortening the time, I ran
WMP and streamed my local NPR, all the while checking with ipconfig
/all if anything was changing.

Two things I noticed were that neither the IP address was changing -
the lease expirations did change every minute - nor was I experiencing
any significant interruptions in the streaming radio. Perhaps gaming
would be different, though, and I might test that later.

Sorry this is so long-winded; perhaps my questions are even mute,
because I don't seem to have a full grasp of how DHCP works. Am I NOT
supposed to get a "new" IP with every lease expiration? Will there be
a significant interruption in my connection?

Thanks for your time and feedback,
Andrew

daytripper wrote:
[edit]
 > If you are constructing "interesting" application port forwards, it's
almost
 > always easiest to do so with static addresses for the target node(s).

 > Systems that are not port forward targets can continue using dhcp
without
 > issue...
[edit]

So if there are only 2 (two) systems on the network, and we're both on
for extended periods of time, then in practice, port forwarding with
DHCP shouldn't be an issue. And if it becomes one, because of a
changed IP address (for example my wife logs on before I do) then I
just need to change the IP address the port is forwarding to, correct?

Thanks!
Andrew<!-- ~MESSAGE_AFTER~ -->