When this happened to me back in the Snap days - the block is based on IP address. So restart your router. (or your PPP session if you are on VDSL to avoid a resync) so you get a new IP address. (check what your current one is first so you can confirm that you have a new one). If that fixes it then the DDoS block will be the problem. Also the block stopped google.com from working while google.co.nz still worked.