It has been several hours since I renewed my domain registration but DNS queries are still returning the previous IP address for my domain. Here is what I have done to troubleshoot:

1) I can see that the new IP address is 99.93.15.153
2) The previous IP address is 162.216.242.208
3) I have run the dynu IP update script with the following response, showing that the script is working.
Saving to: ‘update?myip=99.93.15.153&username= .....
4) I cleared the DNS cache on my linux host, but I still get the previous IP address returned when I do a nslookup or dig, as follows:

;; ANSWER SECTION:
funkietown.com. 107 IN A 162.216.242.208

;; AUTHORITY SECTION:
funkietown.com. 107 IN NS dns2.anycast.dynu.com.
funkietown.com. 107 IN NS dns1.anycast.dynu.com.

;; ADDITIONAL SECTION:
dns1.anycast.dynu.com. 107 IN A 162.216.242.224
dns2.anycast.dynu.com. 107 IN A 45.79.53.60

5) Note that I did the same on my iMac, which is on the same network, with the same results.

6) Looking at the firewall configuration I can see that the WAN IP is 99.93.15.153

Thanks in advance,
Bill Jones

Just for users that may run into this issue again, dns1.anycast.dynu.com is Dynu's expired name server. The DNS will take 6-24 hours to restore due to DNS cache. If you have renewed the domain after it has expired. You will need to wait that long for the DNS to restore.