Hey guys, 
I'm having the issue mentioned in the title.  This just happened two days ago, after power cycling the parent router (Shaw HiTron Modem/Router).  Previous to that using the DIR-825 as an AP was working splendidly.  
The settings I had were as follows;
DIR-825
DHCP OFF, DNS Relay OFF, IP ADDRESS 192.168.0.1, cable plugged into LAN port 1
HiTron Modem/Router
IP ADDRESS 192.168.0.254, everything else left as is
After restarting the Shaw modem/router I have not be able to access the internet.  I've checked my wireless devices (phones, tablets, etc...) IP addresses and they're in the range of 25.68.xx.xx.  So, totally out of range.  I have no idea what is causing this.  
I installed the latest firmware on the DIR-825, and reset to factory settings.  Then I changed all the settings back to what they were previously, as shown above.  Again, I only power cycled the shaw modem, so the settings haven't changed. 
I'm currently at work, so I'm providing this information from memory to best of my knowledge. 
Edit:  The DIR-825 I have is rev B and is running firmware 2.09NA.