*update how to (RFC 2616) refs: https://www.dyndns.com/developers/specs/syntax.html *requirements 1) first, register the DDNS serices liks as www.dyndns.org 2) config router in detail R1(config)#ip ddns update method testddns ; testddns is Dynamic DNS update method name R1(DDNS-update-method)#http R1(DDNS-HTTP)#add http://test:test@members.dyndns.org/nic~~ ; update url R1(DDNS-HTTP)#interval ma..