Method for protecting and searching host in internet protocol version 6 network

A host blocking and searching method in IPv6(Internet Protocol version 6) network for using an NA packet is provided to manage primary network resources in IPv6 environment and build a security environment by blocking the network access of an unauthorized host. A searched IP(Internet Protocol) transmits an NS(Neighbor Solicitation) packet in an ICMPv6(Internet Control Message Protocol version 6) target address and requests host information including link-layer address information and address information(S11). It determines whether an NA(Neighbor Advertisement) packet of the search IP is received(S13). If the NA packet is received, the host information is obtained in the NA packet(S14).