Secure tunnel domain name management

A system, comprising:

• a domain name system (DNS) server in a private network;
• a client terminal in a public network;
• a memory in the client terminal configured to store a DNS cache, wherein the DNS cache is configured to cache a plurality of network addresses associated with the private network, and wherein the private network is coupled to the client terminal using a virtual private network (VPN) connection;
• and
• a processor configured to execute a user-level process to maintain the DNS cache, to intercept socket calls directed to the DNS server in the private network after the VPN connection is established, and to locally return a network address associated with a domain name without sending a resolution request for the domain name to the DNS server if the network address is stored in the DNS cache;
• and
• sending the resolution request for the domain name to the DNS server in the private network if the network address associated with the domain name is not stored in the DNS cache.

A method, comprising:

• establishing a virtual private network (VPN) connection between a client in a public network and a server in a private network;
• intercepting a socket call from the client requesting resolution of a domain name in the private network after the VPN connection has been established;
• searching a local linked list, maintained by the client as a cache, for a network address associated with the domain name;
• locally returning the network address to the client without sending a request to resolve the domain name to a domain name system (DNS) server in the private network if the network address is found in the local linked list;
• and
• if the network address is not found in the local linked list, sending the request to resolve the domain name to the DNS server.

A method, comprising:

• establishing a virtual private network (VPN) connection between a client in a public network and a server in a private network;
• sorting a local linked list, maintained by the client as a cache, according to a number of times a domain name associated with a network address in the private network has been requested;
• intercepting a socket call from the client requesting resolution of the domain name after the VPN connection has been established;
• searching the local linked list for a network address associated with the domain name;
• locally returning the network address to the client without sending a request to resolve the domain name to a domain name system (DNS) server in the private network if the network address is found in the local linked list;
• and
• periodically sending the request to resolve the domain name to the DNS server via the VPN connection upon expiration of a timer associated with the local linked list and the domain name.