In 1996 RFC 1876 was published. It specifies a “Means for Expressing Location Information in the Domain Name System” using the LOC DNS resource record. The LOC record format contains a latitude and longitude as well as altitude and the diameter of a sphere containing the geographical domain.

In today’s Internet, describing the physical area which a domain covers is probably useless as most domains serve a huge geographic area; think “Google”. What I do still find interesting is the use of the LOC record to describe the headquarters of a domain.

I was curious as to how many domains actually contain a LOC resource, so I took a sampling of 284387 existing domains and queried the DNS for the LOC resource record at their zone apex, finding that only 326 domains of those queried actually contain a LOC record; that is round about 1 per mil. (The map above contains a marker for each of the zones that have a LOC record published.)

An example LOC record looks like this:

dig loc
;; ANSWER SECTION: 43200 IN LOC 61 11 0.000 N 149 50 0.000 W 10.00m 1000m 10000m 10m

Net::DNS:RR:LOC kindly translates this data to a lat/long coordinate pair, resulting in 61.1833333333333 -149.833333333333

which I used as data for the Google maps API. You can use Stéphane Bortzmeyer’s query-loc utility from the command line; it does a bit of work in finding the LOC. If you know the exact domain use dig.

Create a LOC record by dropping a pin on a map or by filling out a form.

DNS and GEO :: 14 Nov 2010 :: e-mail