There is an issue related to the Vigor120’s somewhat weak DNS proxy which can potentially cause slow loading or even prevent the loading of certain websites and or pages.
By default, the Vigor120 sets client machine’s DNS servers to its own IP, and proxies the request out to the ISP’s DNS servers automatically. However, the Vigor120 sometimes encounters problems when the DNS proxy doesn’t handle long hostnames correctly – such as those used by CDNs like YouTube.
Configuring the Vigor120 to assign the ISP’s DNS servers directly to the client machines has been known to fix the issue. This can be found under LAN >> General Setup and setting the DNS Server IP Addresses shown on the bottom right with your ISP's DNS Addresses.