VLAN Router with Firewall Supporting Multiple Security Layers
A router containing a firewall capable of supporting a plurality of different security levels. The router of the present invention creates a plurality of Virtual Local Area Networks (VLANs) using a network switch. The VLAN Rules Table (VRT) allows a network administrator to designate a trust level for each VLAN. The trust level may be different for every VLAN and the administrator may designate different rules for each VLAN. The Security Program (SP) analyzes each packet passing through the firewall and determines if the packet is permitted under the rules for the VLAN trust level. An alternative embodiment in which the switch in the router is divided into a plurality of sub-switches is also disclosed. In the alternative embodiment, the firewall need only compare the packet to rules which were not applied in the lower trust levels, eliminating the redundant rules from the comparison process.
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The present invention is directed generally to a security apparatus for a computer network and specifically to a firewall for a plurality of networks with different security levels.
BACKGROUND OF THE INVENTIONA packet is a discrete amount of data transmitted between computers. Packets are transmitted from one computer to another computer using a protocol. Transmission Control Protocol (TCP) is a common protocol and governs the breakup, transmission, reassembly, and verification of the complete messages from one computer to another via Internet Protocol (IP) addresses. Many other types of protocols exist including Simple Mail Transfer Protocol (SMTP), Point to Point Protocol (PPP), Internet Control Message Protocol (ICMP), and User Datagram Protocol (UDP). Packets contain a header containing the IP source address, the IP destination address, the type of protocol (i.e. TCP, UDP, or ICMP), the TCP or UDP source port, the TCP or UDP destination port, and the ICMP message type. Use of protocols to transmit packets is well known in the art.
Firewalls are used in designing and building computer networks and are also well known in the art. A firewall is a device that filters data between two computers or networks to insure that one computer or network is more secure than the other computer or network. Firewalls are divided into one of two categories depending on their function. Packet filtering firewalls are used when connecting to the Internet to keep worms and viruses away from the protected computers. Proxy firewalls are used to monitor, control, and record outbound traffic to the Internet. The traffic consists of packets transmitted from one computer or network to another computer or network.
The internal structure of a packet filtering firewall contains a switch connected to two computers or networks and a set of rules stored in memory. When one computer or network attempts to transmit a packet through a firewall to another computer or network, the firewall analyzes the packet and determines if the rules in the firewall permit or deny passage of the packet. The rules are specific to the packets and are defined by security policies. Policies are broader than rules and define what type of access the protected computer should have. For example, if the security policy were to prohibit access to pornographic websites, then the rules would prohibit X-rated material, vulgar words, and so forth. While the security policies tend to broadly define the limits of the computer's access to the Internet, each rule is very specific in the type of packet permitted or denied from being transferred across the firewall. As an example, a very simple set of rules would look like:
Generally, if the packet is not permitted by one of the rules, the packet is denied. Because of the technical and complex nature of rules, the creation and order of rules is best accomplished by a person of ordinary skill in the art.
A router is a device which connects a plurality of computers or computer networks to the Internet. Routers are also well known in the art. Because routers and firewalls are frequently used together, it is common for packet filtering firewalls to be installed within routers.
One of the shortcomings of prior art firewalls is that the firewalls only create two security levels: a secured area and an unsecured area. However, when configuring a complicated computer network, such as an intranet, many different security levels are desired. In order to achieve multiple security levels, a network administrator must install a plurality of prior art routers and/or firewalls in the intranet.
One of the problems with the computer network configuration depicted in
The prior art firewalls are limited in that an individual firewall is needed for each security boundary. Even with the prior art routers supporting multiple computer networks, the firewall within the router is not able to create different security levels within the individual computer networks. Because a router can connect to multiple computer networks, it would be useful if the firewall could create multiple security levels in the computer networks because a network administrator could then utilize a single firewall where a plurality of firewall were previously required. In other words, the network administrator will have created a plurality of virtual firewalls from a single firewall. Therefore, a need exists in the art for a firewall that allows a network administrator to create multiple security levels using a single firewall.
SUMMARY OF THE INVENTIONThe present invention, which meets the needs identified above, is a router containing a firewall capable of supporting a plurality of different security levels. The router of the present invention creates a plurality of Virtual Local Area Networks (VLANs) using a network switch. The switch is connected to the firewall of the present invention which includes a processor capable of executing instructions from a memory. The memory contains a Configuration Program (CP), a Security Program (SP), a VLAN Rules Table (VRT), and the rules that the firewall applies to the packets. The CP configures the VRT and rules. The SP analyzes each packet passing through the firewall and determines if the packet is permitted under the rules. The SP allows packets permitted under the rules to pass to their destination and denies all other packets. The firewall of the present invention represents a significant improvement over the prior art in that the VRT allows a network administrator to designate a trust level for each VLAN. The trust level may be different for each VLAN and the administrator may designate different rules for each trust level. The administrator may also add, delete, or modify the rules or trust levels using the present invention. Thus, the present invention allows the administrator to utilize a single firewall where a plurality of firewalls were previously required.
In an alternative embodiment of the present invention, the switch in the router is divided into a plurality of sub-switches. Packets passing into the switch pass from one sub-switch to another until they reach a sub-switch connected to the packet's destination. At each sub-switch, the firewall analyzes the packet to determine if it is permitted under the rules for that particular sub-switch. When the packet is passed to a more secure sub-switch, the firewall need only compare the packet to the rules which were not applied in the lower trust levels. Thus, the invention eliminates the redundant rules from the comparison process at each sub-switch. The elimination of the redundant comparisons reduces the comparison time at each sub-switch and, therefore, the residence time of the packet in the firewall.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
As used herein, the term “analyze” shall mean to compare a packet to a list of rules associated with a trust level and determine if the rules permit or deny the packet.
As used herein, the term “computer” shall mean a machine having a processor, a memory, and an operating system, capable of interaction with a user or other computer, and shall include without limitation desktop computers, notebook computers, personal digital assistants (PDAs), servers, handheld computers, and similar devices.
As used herein, the term “deny” shall mean to block transmission of a packet from a source to a destination at a firewall.
As used herein, the term “firewall” shall mean a system or device that enforces a security boundary between two or more computers or computer networks.
As used herein, the term “packet” shall mean a discrete quantity of data transmitted from a source to a destination.
As used herein, the term “permit” shall mean to allow transmission of a packet from a source, though a firewall, and to a destination.
As used herein, the term “policy” shall mean a set of rules governing acceptable use of computing resources, security practices, and operational procedures.
As used herein, the term “residence time” shall mean the time required for a firewall to analyze and either permit or deny a packet.
As used herein, the term “router” shall mean a system or device containing a firewall which connects a computer or computer network to another computer, another computer network, or the Internet.
As used herein, the term “rule” shall mean a criterion for permitting or denying passage of a packet from a source to a destination.
As used herein, the term “switch” shall mean a device capable of receiving a packet, allowing a firewall to analyze the packet, and forwarding the packet to the port associated with the packet's destination.
As used herein, the term “trust level” shall mean a security level associated with a particular set of rules in a firewall.
As used herein, the term “VLAN” is an acronym for “Virtual Local Area Network” and shall mean a computer network consisting of groups of hosts that are on physically different computer networks but that communicate as though they were on the same computer network. Separate VLANs are differentiated by different IP addresses.
The present invention is a router containing a firewall which creates a plurality of different security levels for a plurality of different VLANs. Turning to
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With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function, manner of operation, assembly, and use are deemed readily apparent and obvious to one of ordinary skill in the art. All equivalent relationships to those illustrated in the drawings and described in the specification are encompassed by the present invention. The novel spirit of the present invention is still embodied by reordering or deleting some of the steps contained in this disclosure. The spirit of the invention is not meant to be limited in any way except by proper construction of the following claims.
Claims
1. A firewall capable of creating a plurality of trust levels for a plurality of computer networks comprising:
- a router and a switch;
- wherein the router only permits a packet to pass to a destination when the destination does not have a trust level higher than a trust level of a source of the packet.
2. The firewall of claim 1 comprising:
- a plurality of rules; and
- a table defining the relationship between the trust levels, the rules, and the computer networks.
3. The firewall of claim 2, wherein the firewall further comprises: a configuration program, wherein the configuration program allows a user to add, delete, or modify the plurality of rules and trust levels in the table.
4. The firewall of claim 2, wherein the firewall further comprises: a security program, wherein the security program analyzes the packet and determines if the plurality of rules permit or deny the packet.
5. The firewall of claim 4, wherein the security program comprises:
- instructions for determining the destination of the packet;
- instructions for determining the appropriate rules to use to analyze the packet using the table;
- instructions for analyzing the packet using the rules;
- instructions for determining if the packet is permitted under the rules;
- responsive to a determination that the rules permit the packet, instructions for permitting the packet; and
- responsive to a determination that the rules deny the packet, instructions for denying the packet.
6. The firewall of claim 5, wherein the security program further comprises:
- responsive to a determination that the rules do not permit or deny the packet, instructions for denying the packet.
7. The firewall of claim 1 wherein the firewall is part of a router.
8. A router comprising:
- a switch connected to a firewall and a plurality of computer networks; and
- wherein the firewall creates a plurality of trust levels and associates a trust level with each computer network so that the router permits a packet to pass to a destination only when the destination does not have a trust level higher than a trust level of a source of the packet.
9. The router of claim 8 wherein the switch comprises a sub-switch, the sub-switch being assigned one of a plurality of trust levels.
10. The router of claim 8 wherein the firewall analyzes the packet using some of the rules; and wherein the rules used in the lower trust levels are excluded from the rules used to analyze the packet.
11. The router of claim 8, wherein the firewall further comprises: a configuration program, wherein the configuration program allows a user to add, delete, or modify the rules and trust levels in the table.
12. The router of claim 8, wherein the firewall further comprises: a security program, wherein the security program analyzes a packet and determines if the rules permit or deny the packet.
13. The router of claim 12, wherein the security program comprises:
- instructions for determining the sub-switch location of the packet;
- instructions for determining a source of the packet;
- instructions for determining a destination of the packet; and
- instructions for determining if the packet is attempting to go to a higher trust level;
- responsive to a determination that the packet is not attempting to go to a higher trust level, instructions for permitting the packet.
14. The router of claim 13, wherein responsive to a determination that the packet is attempting to go to a higher trust level, the security program further comprises:
- instructions for determining the appropriate rules to use to analyze the packet using the table;
- instructions for analyzing the packet using the rules;
- instructions for determining if the packet is permitted under the rules;
- responsive to a determination that the rules permit the packet, instructions for permitting the packet; and
- responsive to a determination that the rules deny the packet, instructions for denying the packet.
15. The router of claim 14, wherein the security program further comprises:
- responsive to a determination that the rules do not permit or deny the packet, instructions for denying the packet.
16. The router of claim 8 wherein the firewall further comprises: a table defining the relationship between the trust levels, the rules, and the computer networks.
17-23. (canceled)
24. A program product operable on a computer, the program product comprising:
- a computer-readable medium;
- wherein the computer-readable medium comprises instructions comprising: instructions for determining the destination of the packet; instructions for accessing a plurality of rules; instructions for determining the appropriate rules to use to analyze the packet; instructions for analyzing the packet using the rules; instructions for determining if the packet is permitted under the rules; responsive to a determination that the rules permit the packet, instructions for permitting the packet; and responsive to a determination that the rules deny the packet, instructions for denying the packet.
25. The computer-readable of claim 24 further comprising: responsive to a determination that the rules do not permit or deny the packet, instructions for denying the packet.
26. The product computer-readable of claim 24 wherein a table defines the relationship between the trust levels, the rules, and the computer networks.
27. A program product operable on a computer, the program product comprising:
- a computer-readable medium;
- wherein the computer-readable medium comprises instructions comprising: instructions for determining the sub-switch location of a packet; instructions for determining a source of the packet; instructions for determining a destination of the packet; instructions for determining if the packet is attempting to go to a higher trust level; and responsive to a determination that the packet is not attempting to go to a higher trust level, instructions for permitting the packet.
28. The computer-readable of claim 27, wherein responsive to a determination that the packet is attempting to go to a higher trust level, the method further comprises:
- instructions for determining the appropriate rules to use to analyze the packet using the table;
- instructions for analyzing the packet using the rules;
- instructions for determining if the packet is permitted under the rules;
- responsive to a determination that the rules permit the packet, instructions for permitting the packet; and
- responsive to a determination that the rules deny the packet, instructions for denying the packet.
29. The computer-readable of claim 28 wherein the security program further comprises: responsive to a determination that the rules do not permit or deny the packet, instructions for denying the packet.
30. The computer-readable of claim 27 wherein the firewall further comprises: a table defining the relationship between the trust levels, the rules, and the computer networks.
31. A firewall capable of creating a plurality of trust levels for a plurality of computer networks comprising:
- a plurality of rules;
- a table defining the relationship between the trust levels, the rules, and the computer networks;
- a configuration program, wherein the configuration program allows a user to add, delete, or modify the rules and trust levels in the table;
- a security program, wherein the security program analyzes a packet and determines if the rules permit or deny the packet, the security program comprising: instructions for determining the destination of the packet; instructions for determining the appropriate rules to use to analyze the packet using the table; instructions for analyzing the packet using the rules; instructions for determining if the packet is permitted under the rules; responsive to a determination that the rules permit the packet, instructions for permitting the packet; responsive to a determination that the rules deny the packet, instructions for denying the packet; and responsive to a determination that the rules do not permit or deny the packet, instructions for denying the packet; wherein the packet is permitted to pass to the destination only when the destination does not have a trust level higher than a trust level of a source of the packet.
32. The firewall of claim 31 wherein the firewall is part of a router.
Type: Application
Filed: Oct 3, 2008
Publication Date: Jan 29, 2009
Applicant: International Business Machines Corporation (Armonk, NY)
Inventors: Kyusun Chang (Austin, TX), John Alan Mims (Round Rock, TX), Allen Keith Wilson (Austin, TX)
Application Number: 12/245,043
International Classification: G06F 21/00 (20060101); G06F 15/16 (20060101);