I have a site which will soon be seeing large quantities of visitors each transferring a very small amount of data. Thus, I'm not concerned as much with performance degredation from page rendering or bandwidth use as I am with DNS overhead. Currently, I run my own nameservers, and haven't run into any problems as of yet. However, all the sites I host currently are consuming a very small amount of traffic as compared to what I will be serving with the launch of a new site.
What are some practical ways to reduce the volume of DNS traffic headed to my server. Now, granted, it has to go somewhere, and the overall amount can be lowered by increasing the TTL, but this isn't what I want to know.
What I'm looking for are places to divert the DNS traffic to. Are there any good and reputable free DNS services in existence (sorry, no granite canyon). I know zoneedit is free up to a point, but I'm not sure if I'd hit the 250MB mark or not.
What I'm currently thinking about doing is creating a subdomain at the registrar level. Say, for example, I would have abc.mydomain.com listed in there with ns1.mydomain.com and ns2.mydomain.com. This would remove the need for my box to handle DNS requests for abc.mydomain.com
If you have more than two-three domains then I'd strongly urge you to consider paid-for service. I am using dnsmadeeasy.com and to date I am very happy with them. They cost $29.95 per year for 50 domains with unlimited traffic.
If you have one or two domains then zoneedit might be your choice. You get five "free" credits with them. Using their DNS for one domain is one way to spend a credit. Another is going over your alloted 200 MB limit. So, with one domain you can have 800 MB of DNS traffic and still be within free limits.
How much traffic are you expecting and what are the specs on your current nameservers? Are they dedicated nameservers? Until recently a couple pIII 1gig machines were doing dns for a couple hundred domains (quite a few of them very busy sites) for me and they never blinked.