LIS Discovery using IP address and Reverse DNS draft-thomson-geopriv-res-gw-lis-discovery-03 Ray Bellis, Advanced Projects, Nominet UK IETF 77, GeoPriv WG Anaheim, 23 rd March 2010

History draft-ietf-geopriv-lis-discovery Uses a domain name to find a (U-)NAPTR record –Domain name obtained via DHCP Previously also took the PTR record for the host and mangled that host name to find the domain name DNS folks (myself included) didn’t like this: –The LIS is part of the local network architecture –But hostnames very often have no relationship to the network architecture

Problem Statement DHCP option rollout will take years, particularly in residential environments What’s your domain name, if PTR records are unsuitable?

Proposed Solution Don’t invent a domain name – there’s already a domain with a 1:1 mapping between IP and name: –in-addr.arpa –ip6.arpa The reverse DNS tree has a very strong association with the underlying network architecture Find your public IP (using STUN) Put the U-NAPTR record directly in the reverse DNS tree

Example STUN says my public IP is Do a lookup for the /32 host address – in-addr.arpa. IN NAPTR? If lookup fails, try at the /24 boundary: – in-addr.arpa. IN NAPTR? If lookup fails, try at the /16 boundary – in-addr.arpa. IN NAPTR? If lookup fails, give up else pass the resulting NAPTR record to the normal LIS Discovery algorithm (Similar process documented for IPv6 addresses)

Next Steps Working Group adoption?