The GridInfo protocol was suggested by mana janus to facilitate autoconfiguration of clients. With the GridInfo protocol a smart client only needs to have the URI of the user server or the standalone server and can then obtain parameters such as the welcome page, the helper URI (for the economy subsystem), the name of the grid and other information automatically.

Retrieving the GridInfo is just a simple HTTP GET call to /get_grid_info on either the standalone server's URL or on the grid's user server:

% GET http://127.0.0.1:9000/get_grid_info | xml_pp
<gridinfo>
  <login>http://127.0.0.1:9000/</login>
  <gridname>the lost continent of hippo</gridname>
  <mode>standalone</mode>
  <register>http://127.0.0.1/register</register>
  <platform>OpenSim</platform>
  <help>http://127.0.0.1/help</help>
  <about>http://127.0.0.1/about/</about>
  <welcome>http://127.0.0.1/welcome</welcome>
  <gridnick>hippogrid</gridnick>
  <password>http://127.0.0.1/password</password>
  <economy>http://127.0.0.1:9000/</economy>
</gridinfo>

which was “generated” by the following [GridInfo] section:

[GridInfo]
; login uri
login = http://127.0.0.1:9000/
; login page
welcome = http://127.0.0.1/welcome
; helper uri
economy = http://127.0.0.1:9000/
; web page of grid
about = http://127.0.0.1/about/
; account creation
register = http://127.0.0.1/register
; help
help = http://127.0.0.1/help
; password help
password = http://127.0.0.1/password
; long grid name
gridname = "the lost continent of hippo"
; short grid name
gridnick = "hippogrid"

Have a look at the option table in the OpenSim.ini section for all GridInfo options — note, that you can add additional keys there, they are automatically included in the response.