Cisco Technology, Inc.

Suresh Satapati

Senthil M Sivakumar

Siva S Jayasenan

Mark Denny

Kaushik Pratap Biswas

Ian Herbert Wilson

Michael J Sullenberger

Douglas McLaggan

Markus G Hies

Jieping Chen

Douglas Mclaggan

Redundant gateway methods, apparatus and systems using more than one gateway device in a gateway device group for communications directed outside of a LAN. Failover services are thus provided in the event that an active router or other gateway device fails. Network address translation (NAT) services are provided simultaneously by having all gateway devices in the redundancy group create and maintain IP aliases and static NAT mappings, while disabling all gateway devices operating in a non-active mode from replying to address resolution protocol requests from hosts. A gateway device may be configured to operate in a redundancy group in an active operating mode or a non-active operating mode. The gateway device handles transmissions into and out of the network to which it is connected only when the gateway device is in the active operating mode so as to avoid system corruption due to ARP activity and message transmissions by non-active gateway devices.

Network address translation with IP redundancy

Methods and apparatus for processing a DNS query by a NAT device are disclosed. A NAT device (e.g., NAT-PT device) receives the DNS query from a node. The NAT device then sends two DNS queries to a DNS server. Specifically, each of the DNS queries requests an IP address in a different version of IP (e.g., IPv4 or IPv6). For example, each of the DNS queries may request an A record or an AAAA record. When the NAT device receives two DNS replies from the DNS server, it forwards only one of the DNS replies to the node. Specifically, the DNS reply that is forwarded includes at least one answer record. DNS replies that do not include at least one answer record, or are received subsequent to forwarding the DNS reply to the node, are dropped by the NAT device.

Apparatus and methods for handling name resolution over IPV6 using NAT-PT and DNS-ALG

Gateway and NAT services to a single host or large number of hosts on a local network using a redundancy group having gateway devices. A pool of unique IP addresses are partitioned into address blocks, one of which is assigned to a gateway device. Using the unique IP addresses in its assigned address block, the gateway device translates local IP addresses of hosts on a local network to unique IP addresses from the gateway device's assigned address block for host packets destined for outside networks and creates a mapping of the translation. The gateway device notifies other gateway devices in the redundancy group of the mapping. A master mapping database or a local mapping database is updated whenever one of the gateway devices performs a translation. In the event that one of the gateway devices ceases forwarding of outgoing packets for a host using the gateway device's virtual MAC address, that virtual MAC address is re-assigned to an operating gateway device in the redundancy group to permit continued forwarding of the host's packets destined for outside networks.

Network address translation with gateway load distribution

Disclosed are methods and apparatus for reliably handling Stream Control Transmission Protocol (SCTP) multi-homed connections across multiple translation (e.g., NAT devices), such that messages sent between endpoints, which include one or more multi-homed devices, reach their intended destination. In one embodiment, a method for handling SCTP multi-homed connections across multiple translation devices is disclosed. When an SCTP association between two hosts is being established through a particular translation device, multi-homing information for one or both of the hosts is communicated from the particular translation device to one or more other translation devices which are associated with the particular translation device. This is done so that the one or more other translation devices can store the received multi-homing information and when data is received at the one or more translation devices for the established SCTP association between the two hosts, the data is then caused to be sent to its intended destination based on the stored multi-homing information. The multi-homing information is also stored for the particular translation device. When data is received at the particular translation device for the established SCTP association between the two hosts, the data is caused to be sent to its intended destination based on the multi-homing information.

Method and apparatus for handling SCTP multi-homed connections

Methods and apparatuses for distributing network address translation. By having a gateway inform inside devices of global addresses, the gateway can avoid performing many functions of a traditional NAT box. Specifically, an inside device is informed of a global address shared by all devices on the inside device's network segment. Each device on that segment would be assigned a range of ports to distinguish messages from separate devices that use the same global address.

Method and apparatus for distributed network address translation processing

Disclosed are methods and apparatus for efficiently and reliably handling DNS (domain name service) PTR (pointer) queries and replies across IPv4 and IPv6 networks. In general terms, an IPv4 DNS PTR query which is sent by an IPv4 device to an IPv6 DNS Server is intercepted or received, for example, by a network device configured with NAT-PT and DNS-ALG. The received IPv4 DNS PTR query is then translated into two different types of IPv6 DNS PTR queries: a query having an 'IP6.INT' string and a query having an 'IP6.ARPA' string. Both types of IPv6 queries are then sent to the IPv6 destination DNS Server. Whether the DNS sends an IP6.ARPA or an IP6.INT type reply or both types of replies back, a valid reply is identified (if present) and then translated before reaching the IPv4 device.

Method and apparatus for handling IPv4 DNS PTR queries across IPv4 and IPv6 networks

A method for transparently sharing at least one IPv4 address among a plurality of hosts wherein at least a first host of the plurality of hosts uses the IPv4 protocol and wherein at least a second host of the plurality of hosts uses an IPv6 protocol is provided. A first data having a first source address and a first destination address is received. A network address translation with port address translation is performed, if the first data is in an IPv4 protocol. A network address translation protocol translation with port address translation is performed, if the first data is in an IPv6 protocol.

Shared port address translation on a router behaving as NAT & NAT-PT gateway

A method for providing handling of data sent between a first network and at least a second network and a third network, wherein the first network is of a first protocol and the at least second and third networks are of a second protocol at least partially overlap is provided. A packet transmitted from the first network is received. The packet has a first address prefix if the packet is directed to the second network and has a second address prefix if the packet is directed to the third network. A destination address of the packet and a source address of the packet are translated from the first protocol to the second protocol. The packet is directed to the second network if the packet has the first address prefix. The packet is directed to the third network if the packet has the second address prefix.

Growing community of inventors

Sunnyvale, CA, United States of America

Suresh Satapati