Having done some research and sought some comments from my ISP here in Australia (Internode), I'm going to have a go at answering my own questions. These answers are based on some pretty quick research none of which was very in depth. However because some of it is based on my Australian ISPs comments, I think it should be taken into account by anyone considering the move to openDNS (or any other DNS).
1. Anyone can use OpenDNS, OpenDNS actually recommends some easy changes to the router (rather than to the LAN settings, though that is fine too.
2. One of the benefits touted to OpenDNS is the control panel control it offers, especially the ability to block addresses. (i.e. content filtering say if you have kids). however to get these "advantages" you will need to register with OpenDNS - which seems a straightforward process. There are plenty of controls one can use through your control panel once you are registered.
3. OpenDNS claims speed improvements to your internet experience through the caching of internet addresses. However the benefits of this claim must be weighed against factors such as your location (I think their main servers are in Palo Alto in the US and maybe London), the quality of your own ISPs caching, and particularly whether your ISP is using any particular servers to provide content.
This means that for me in Australia on Internode, the OpenDNS resolvers are at least 12 hops away from me (if its Palo Alto) - roughly 200ms and the NODE DNS servers are maximum 4 hops away - about 40ms so the benefits may be illusory.
Also, if If I only access domains that are:
- unlikely to have been accessed by anyone at my ISP recently.
- nameservers responding to those domain queries are further away in response time than the the OpenDNS resolvers then there might
be a speed increase. A few milliseconds here and there, otherwise the speed benefits may not exist. Network latency dominates DNS resolution time
. The Pacific Ocean is the problem here.
Perhaps more importantly is that at least in Australia, as much as we complain, many of our ISPs are of high quality and provide additional benefits (partly because of our distance from e.g. California). In the words of the Internode rep:
Whilst customers are free to use it (OpenDNS), we don't recommend it as it will often lead to a lower performance service as, for example, Akamai delivered content will often be delivered from servers off shore rather than on our network.
The Akami delivered content is particularly important with streaming video and audio, but generally things like big downloads and the like. (This includes Microsoft Download and Microsoft Update).
So it seems that if you are accessing addresses which are rarely used and therefore not cached with your ISP you may
observe some speed benefits, but at least in Australia, these are going to be pretty marginal.
OpenDNS will give the greatest benefits if you are with a crappy ISP, relatively close to OpenDNS servers, or if you want the benefits of their user control panel (filtering), or only access addresses unlikely to be cached by your ISP or near to you (geographically). May I suggest that some comment be made in the header of the tutorial which incorporates some of the issues raised here.