Abstract: A network address translation gateway provides normal network translation for IP datagrams traveling from a local area network using local IP addresses to an external network, but suspends source service address (port) translation when the port is reserved for a specific protocol, such as the ISAKMP “handshaking” protocol that is part of the IPSec protocol model. ISAKMP exchanges require both source and target computers to use the same service address (port). By providing a network interface that does not translate the source service address (port), this gateway enables the initiation and maintenance of secure, encrypted transmissions using IPSec protocol between a local area network using local IP addresses and servers on the internet.

Abstract: A network address translation gateway provides normal network translation for IP datagrams traveling from a local area network using local IP addresses to an external network, but suspends source service address (port) translation when the port is reserved for a specific protocol, such as the ISAKMP “handshaking” protocol that is part of the IPSec protocol model. ISAKMP exchanges require both source and target computers to use the same service address (port). By providing a network interface that does not translate the source service address (port), this gateway enables the initiation and maintenance of secure, encrypted transmissions using IPSec protocol between a local area network using local IP addresses and servers on the internet.

Abstract: A network address translation gateway provides normal network translation for IP datagrams traveling from a local area network using local IP addresses to an external network, but suspends source service address (port) translation when the port is reserved for a specific protocol, such as the ISAKMP “handshaking” protocol that is part of the IPSec protocol model. ISAKMP exchanges require both source and target computers to use the same service address (port). By providing a network interface that does not translate the source service address (port), this gateway enables the initiation and maintenance of secure, encrypted transmissions using IPSec protocol between a local area network using local IP addresses and servers on the internet.

Abstract: A network address translation gateway (20) provides normal network translation for IP datagrams traveling from a local area network (10) using local IP addresses to an external network (30), but suspends source service address translation when the port is reserved for a specific protocol, such as the ISAKMP “handshaking” protocol that is part of the IPSec protocol model (FIGS. 2&3). ISAKMP exchanges require both source and target computers to use the same service address. By providing a network interface that does not translate the source service address, this gateway enables the initiation and maintenance of secure, encrypted transmissions using IPSec protocol between a local area network using local IP addresses and servers on the internet.

Abstract: A method of using point-to-point protocol (PPP) to transmit information from a device connected to an ethernet network, comprises the steps of identifying each packet having an IP header that is transmitted from the device, analyzing each IP packet to determine whether a TCP packet has been encapsulated within a PPP packet within the IP packet, and, if so, determining whether the SYN flag within the header of the TCP header is set, and if the SYN flag is set, modifying the value of the Maximum Segment Size in the TCP header to be no larger than 1452 bytes, and transmitting said packet to the destination address appearing in said IP header.