Abstract: A method for authenticating packet communication traffic includes receiving a data packet sent over a network from a source address to a destination address and reading from the packet a value of a field that is indicative of a number of hops traversed by the packet since having been sent from the source address. The authenticity of the source address is assessed responsive to the value.

Abstract: A method for communication includes coupling a first port of a Layer-3 packet router to receive communication traffic from a network, the traffic including packets destined for a target address, which is accessible via a second port of the router. At the router, the packets that are destined for the target address are diverted to a traffic processor via a third port of the router. The diverted packets are processed at the traffic processor, and returning the processed packets to the router via the third port. At the router, the processed packets are conveyed from the third port to the second port for delivery to the target address.

Abstract: A method for authenticating communication traffic includes receiving a first request, such as a DNS request, sent over a network from a source address, to provide network information regarding a given domain name. A response is sent to the source address in reply to the first request. When a second request is from the source address in reply to the response, the authenticity of the first request is assessed based on the second request.

Abstract: A method for authenticating communication traffic includes receiving a first request, such as a DNS request, sent over a network from a source address, to provide network information regarding a given domain name. A response is sent to the source address in reply to the first request. When a second request is from the source address in reply to the response, the authenticity of the first request is assessed based on the second request.

Abstract: A method for authenticating communication traffic includes intercepting a request directed over a network from a source address to open a connection to a target computer in accordance with a handshake procedure specified by a predetermined communication protocol. A reply to the request that deviates from the specified handshake procedure is sent to the source address. A response from the source address to the reply is analyzed in order to make an assessment of legitimacy of the source address. Upon determining, based on the assessment, that the source address is legitimate, the target computer is permitted to complete the handshake procedure so as to open the connection with the source address.

Abstract: A method for authenticating packet communication traffic includes receiving a data packet sent over a network from a source address to a destination address and reading from the packet a value of a field that is indicative of a number of hops traversed by the packet since having been sent from the source address. The authenticity of the source address is assessed responsive to the value.

Abstract: A method for authenticating communication traffic includes receiving a first request, such as a DNS request, sent over a network from a source address, to provide network information regarding a given domain name. A response is sent to the source address in reply to the first request. When a second request is from the source address in reply to the response, the authenticity of the first request is assessed based on the second request.