WEEK XI

INTRODUCTION - IPV4 AND IPV6 ADDRESS MANAGEMENT

INTRODUCTION - IPV4 AND IPV6 ADDRESS MANAGEMENT

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• IPAM (IP Address Management) is the administration of DNS and DHCP, which are the network services that assign and resolve IP addresses to machines in a TCP/IP network.
• IPAM is a means of planning, tracking and managing the Internet Protocol address space used in a network.
• Most commonly, tools such as DNS and DHCP are used together to perform this task.
• IPAM refers to a method of IP scanning, IP address tracking and managing the information associated with a network's Internet Protocol address space and IPAM system.

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Network boundaries

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• Are the limits that define where a network begins and ends.
• They are used to specify the range of devices and services that are allowed on the network.
• Network boundaries are also used to protect the network from unauthorized access and malicious attacks.
• Network boundaries are important for organizations because they help to secure their networks from external threats.
• They also help to ensure that only authorized users are allowed access to the network.
• Without network boundaries, malicious attackers could gain access to sensitive data or disrupt network operations.
• Network boundaries can be physical or virtual.
• Physical boundaries are typically used to separate different networks or subnets.

GATEWAYS TO OTHER NETWORKS

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• Network gateways are designed to transmit traffic between networks, while the primary purpose of a network firewall is to restrict what traffic can pass through a network boundary.
• Network firewalls have built-in rule sets that determine whether or not a particular packet meets the corporate security policy.
• Network gateways are tasked with linking networks by performing translation between different protocols and data formats at the network boundary.
• Companies may deploy gateways to connect the corporate LAN to the public Internet or to link different internal networks, such as IT and OT networks.

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ROUTERS AS GATEWAYS

• Gateways and routers are similar in that they both can be used to regulate traffic between two or more separate networks.
• A router is used to join two similar types of networks and a gateway is used to join two dissimilar networks.
• Dissimilar could be used to describe networks that use different primary protocols.
• Due to this logic, a router may be considered a gateway, but a gateway is not always considered a router.
• Routers are the most common gateway, used to connect a home or enterprise network to the internet.
• Both routers and gateways are hardware components in a network that regulate traffic and determine its flow between two or more networks.
• Sometimes, a network may use routers - both as end-point and access-point, in this case, the router becomes a gateway.

• If wireless Internet (WiFi) is needed, then a router should be used. If separate devices are not to be used then get a gateway – also called a cable modem router – which is a device that is both a cable modem and router.
• Both router and gateway transfer data among various networks.
• But there is a fundamental difference between router and gateway.
• A router is a networking layer system that can be used for managing and forwarding the data packets into various computer networks.
• A gateway is very different.
• It is hardware or a device that acts as a gate among various available networks.
• It also acts as a node that serves as an entry point for various other networks.

NETWORK ADDRESS TRANSLATION

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• Network Address Translation (NAT) is a service that is used in routers.
• Its purpose is to translate a set of IP addresses to another set of IP addresses.
• A workstation inside a network makes a request to a computer on the Internet.
• Routers within the network recognize that the request is not for a resource inside the network, so they send the request to the firewall. 
• The firewall sees the request from the computer with the internal IP.
• It then makes the same request to the Internet using its own public address and returns the response from the Internet resource to the computer inside the private network.

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NAT OPERATION

• The NAT mechanism ("natting") is a router feature, and is part of a corporate firewall.
• NAT gateways can map IP addresses in several ways:
• from a local IP address to one global IP address statically;
• hiding an entire IP address space comprised of private IP addresses behind a single IP address;
• to a large private network using a single public IP address using translation tables;
• from a local IP address plus a particular TCP port to a global address or a pool of public IP addresses;
• from a global IP address to any of a pool of local IP addresses on a round-robin basis.

Fig.: Configuration of NAT

IPV4 ISSUES

• The IPv4 is defined by IETF RFC 791.
• Initial design of IPv4 did not anticipate the growth of internet and this created many issues, which proved IPv4 need to be changed.
• The main limitations of IPv4 are listed below.

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1. The lack of address space - the number of different devices connected to the Internet grows exponentially, and the size of the address space is quickly depleted;

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2. Weak protocol extensibility - the insufficient size of the IPv4 header, which does not accommodate the required number of additional parameters;

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3. The problem of security of communications - no means are provided to limit access to information hosted on the network. IPv4 has never been designed for security.

- Originally designed as an isolated military network

• Then adapted for public education and research network

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4. Lack of quality of service support - placement of information about bandwidth, delays required for smooth operation of some network applications are not supported;

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5. Geographic limitations - since the Internet was created in the USA, this country is also involved in the distribution of IP addresses. Almost 50% of all addresses are reserved for the United States.

NEED OF IPV6

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• IPv6 is the latest version of the Internet Protocol, which identifies devices across the internet so they can be located.
• Every device that uses the internet is identified through its own IP address in order for internet communication to work.
• So IPv6 can be considered just like the street addresses and zip codes you need to know in order to mail a letter.

Key benefits to IPv6 include:

• No more NAT (Network Address Translation)
• Auto-configuration
• No more private address collisions
• Better multicast routing
• Simpler header format
• Simplified, more efficient routing
• True quality of service (QoS), also called "flow labeling"
• Built-in authentication and privacy support
• Flexible options and extensions
• Easier administration (no more DHCP)

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IPV4 vs IPV6

IPV4 and IPV6 COEXISTENCE

• IPv4-IPv6 coexistence can be achieved by mainly three techniques.
• One is dual stack, where your network hardware runs IPv4 and IPv6 simultaneously.
• The second one is tunnel, meaning encapsulating IPv6 packets within IPv4 packets.
• Network Address Translation (NAT) by which a device translates IPv6 packets into IPv4 packets or vice versa.

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IPV6 FEATURES

• Larger address space
• Simplified header
• End-to-end connectivity
• Auto-configuration
• Faster forwarding or routing

• Stronger security through IPSec
• No broadcast
• Anycast support
• Greater mobility
• Enhanced priority support
• Smooth transition
• Extensibility

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IPV6 ADDRESS REPRESENTATION

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• An IPv6 address is 128 bits in length and consists of eight, 16-bit fields, with each field bounded by a colon.
• Each field must contain a hexadecimal number, in contrast to the dotted-decimal notation of IPv4 addresses.
• In the fig., the x represents hexadecimal numbers.
• IPv6 defines three address types – Unicast, Multicast and Anycast

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Fig: Examples of IPv6 addresses.

CONCEPT OF VIRTUAL LANs (VLANs)

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• VLAN is a custom network which is created from one or more local area networks.
• It enables a group of devices available in multiple networks to be combined into one logical network.
• The result becomes a virtual LAN that is administered like a physical LAN.

• A virtual local area network - VLAN is a virtualized connection that connects multiple devices and network nodes from different LANs into one logical network