A network access manager controls access to a network interface according to a set of access control instructions specifying permissible and impermissible addresses and domains on a network. The network access manager establishes a graylist of addresses based on a domain request that is associated with a whitelisted domain that is accessed via a blacklisted address. When a request to establish a connection is received directed to a graylisted address, the connection is permitted to establish and the connection is added to a session graylist. When a session data transfer packet is received, if the session corresponds to a session on the session graylist, the session data transfer packet is examined to determine if it matches a whitelisted domain, in which case the session is associated with a session whitelist and permitted access to the network. The access control instructions may be automatically updated from a trusted access control management system.