International Business Machines Corporation

Sumisho Computer Systems Corporation

Donald T Davis, Jr

David A Kranz

Michael T Evans

Elizabeth A Martin

Mathew J Hostetter

Mechanisms are provided for performing an operation on a received data packet. A data packet is received and a hash operation on a header field value of a header of the data packet is performed to generate a hash value. A lookup operation is performed in a hash table associated with a type of the header field value to identify a hash table entry. A bit string associated with the hash table entry is retrieved, where each bit in the bit string corresponds to a class of rules of a rule set of a firewall. A matching operation of the header field value to rules in classes of rules corresponding to bits set in the bit string is performed to select one or more search trees. Operations are performed based on rules in the classes of rules being matched by header field value of the data packet.

Firewall packet filtering

Mobile code, such as an applet, is permitted to create a network connection with a content server on a network, without restricting the applet only to connections from the computer from which it was downloaded. This is achieved in accordance with the principles of the present invention by using network restriction software in the execution engine or runtime system under which the applet executes. When the applet attempts to create a network connection to a content server, the network restriction software checks a name file on the content server for the presence of an entry whose name corresponds to the name of the computer from which the applet was downloaded. If such an entry is present, then the network restriction software permits the network connection between the applet and the content server to be created. If not, the applet may not create a network connection with the content server.

System and method for specifying access to resources in a mobile code system

A system and methods are disclosed that permit mobile code, such as an applet, to create a network connection with a content server on a network, without exposing the client computer that is running the applet, or other computers with which the client computer may communicate, to a DNS spoofing attack. This is achieved in accordance with the principles of the present invention by using network restriction software in the execution engine or runtime system under which the applet executes. When the applet attempts to create a network connection to a content server, the network restriction software checks a 'name directory' on the content server for the presence of an entry whose name corresponds to the name of the computer from which the applet was downloaded. If such an entry is present, then the network restriction software permits the network connection between the applet and the content server to be created. If not, the applet may not create a network connection with the content server. Additionally, address checks may be applied to assist in preventing DNS spoofing attacks from succeeding.

Growing community of inventors

Somerville, MA, United States of America

Donald T Davis, Jr