DHCP problems in -current?

I'm trying to figure out if the problems I'm having with DHCP are on my end 
(I'm a client) or on the DHCP server's end. Every 15-30 minutes I'm assigned 
a new IP. When I looked through my logs for four months before the problem 
started, I noticed I was only assigned a new IP once in all that time before 
this started. I contacted my ISP, who verified that was an abnormal frequency 
of IP change, and they did fix something which made my computer stop 
complaining that someone else was using my IP (that was due to a security 
issue with another computer). But I'm still getting a new IP every 15 
minutes.

The problem started exactly when I upgraded from a Dec. 28 -current to a Jan. 
20 -current (which is one reason I think it's on my end). I noticed that 
src/contrib/isc-dhcp/client/dhclient.c was modified in that time - with a 
commit log that sounds as if it would _solve_ problems like this, rather than 
start them. Right now I'm running -current from Jan 26, with the same 
problem.

I don't see a pr on this subject. Is it a known problem, or likely a 
configuration problem with my ISP?

Thanks,

-David

-- 
Department of Physics
The University of Washington, Seattle