CCNA1 IPv6

Transitioning to IPv6

mobile providers have been leading the way with the transition to IPv6. The top two mobile providers in the United States report that over 90% of their traffic is over IPv6. Most top ISPs and content providers such as YouTube, Facebook, and NetFlix, have also made the transition Many companies like Microsoft, Facebook, and LinkedIn are transitioning to IPv6-only internally

IPv6 range

providing 340 undecillion

IPv6 DFG

router LLAs are used as default gateway addresses and in routing advertisement messages

IPv6 default gateway

The default gateway address can only be obtained dynamically from the RA message. The stateless or stateful DHCPv6 server does not provide the default gateway address.

IPv6 GUA structure

"Global Routing Prefix" - it is common for an ISPs to assign a /48 global routing prefix to its customers -The global routing prefix will usually vary depending on the policies of the ISP -the IPv6 address 2001:db8:acad::/48 has a global routing prefix that indicates that the first 48 bits (3 hextets) (2001:db8:acad) is how the ISP knows of this prefix (network). -The size of the global routing prefix determines the size of the subnet ID "Subnet ID" -The Subnet ID field is the area between the Global Routing Prefix and the Interface ID -Unlike IPv4 where you must borrow bits from the host portion to create subnets, IPv6 was designed with subnetting in mind. The Subnet ID is used by an organization to identify subnets within its site. The larger the subnet ID, the more subnets available -Many organizations are receiving a /32 global routing prefix. Using the recommended /64 prefix in order to create a 64-bit Interface ID, leaves a 32 bit Subnet ID -Using a typical /64 prefix length, the first four hextets are for the network portion of the address, with the fourth hextet indicating the Subnet ID. The remaining four hextets are for the Interface ID. "Interface ID" -The IPv6 interface ID is equivalent to the host portion of an IPv4 address -The term Interface ID is used because a single host may have multiple interfaces, each having one or more IPv6 addresses -The term Interface ID is used because a single host may have multiple interfaces, each having one or more IPv6 addresses

IPv6 structure

* IPv6 addresses are 128 bits in length and written as a string of hexadecimal values * Every four bits is represented by a single hexadecimal digit; for a total of 32 hexadecimal values * Pv6 addresses are not case-sensitive and can be written in either lowercase or uppercase * x:x:x:x:x:x:x:x, with each "x" consisting of four hexadecimal values

Rule 2- Double Colon

-2001:db8:cafe:1:0:0:0:1 (leading 0s omitted) could be represented as 2001:db8:cafe:1::1. The double colon (::) is used in place of the three all-0 hextets (0:0:0). -The double colon (::) can only be used once within an address -This is commonly known as the compressed format -Here is an example of the incorrect use of the double colon: 2001:db8::abcd::1234 -If an address has more than one contiguous string of all-0 hextent, the best practice is to use the double colon (::) on the longest string. If the strings are equal, the first string should use the double colon (::)

Method 3: Stateful DHCPv6

-A router interface can be configured to send an RA using stateful DHCPv6 only -the client needs to configure the router's LLA, which is the RA source IPv6 address, for the default gateway address. - and then needs to go to A stateful DHCPv6 server to obtain a GUA, DNS server address, domain name and other necessary information.

Solicited-Node IPv6 Multicast Addresses

-A solicited-node multicast address is similar to the all-nodes multicast address -The advantage of a solicited-node multicast address is that it is mapped to a special Ethernet multicast address -This allows the Ethernet NIC to filter the frame by examining the destination MAC address without sending it to the IPv6 process to see if the device is the intended target of the IPv6 packet

serial interface

-A type of interface on a router, used to connect to some types of WAN links, particularly leased lines and Frame Relay access links. -As we all know Serial interfaces do not have mac addresses, so the answer would no mac-address. MAC address is used only on Ethernet interfaces, not on serial ones. -so, For serial interfaces, the router will use the MAC address of an Ethernet interface to create its LLA

Well-known multicast addresses

-Well-known IPv6 multicast addresses are assigned. -Assigned multicast addresses, are reserved multicast addresses, for predefined groups of devices. -An assigned multicast address is a single address used to reach a group of devices running a common protocol or service -Assigned multicast addresses are used in context with specific protocols such as DHCPv6.

LInk-Local attributes

-An IPv6 link-local address (LLA) enables a device to communicate with other IPv6-enabled devices on the same link and on that link only (subnet) -Packets with a source or destination LLA cannot be routed beyond the link from which the packet originated -The GUA is not a requirement. However, every IPv6-enabled network interface must have an LLA -If an LLA is not configured manually on an interface, the device will automatically create its own without communicating with a DHCP server -IPv6-enabled hosts create an IPv6 LLA even if the device has not been assigned a global unicast IPv6 address. This allows IPv6-enabled devices to communicate with other IPv6-enabled devices on the same subnet. This includes communication with the default gateway (router). -IPv6 LLAs are in the fe80::/10 range -The /10 indicates that the first 10 bits are 1111 1110 10xx xxxx. The first hextet has a range of 1111 1110 1000 0000 (fe80) to 1111 1110 1011 1111 (febf). -the hosts use LLA as Default -Gateway -Routers use the LLA of neighbor routers to send routing updates. "There are two ways that a device can obtain an LLA": -Statically - This means the device has been manually configured. -Dynamically - This means the device creates its own interface ID by using randomly generated values or using the Extended Unique Identifier (EUI) method, which uses the client MAC address along with additional bits.

Multicast

-An IPv6 multicast address is used to send a single IPv6 packet to multiple destinations.

Dynamic LLA

-Cisco routers automatically create an IPv6 LLA whenever a GUA is assigned to the interface -Cisco IOS routers use EUI-64 to generate the interface ID for all LLAs on IPv6 interfaces -For serial interfaces, the router will use the MAC address of an Ethernet interface -Recall that an LLA must be unique only on that link or network -However, a drawback to using the dynamically assigned LLA is its long interface ID

Randomly Generated Interface IDs

-Depending upon the operating system, a device may use a randomly generated interface ID instead of using the MAC address and the EUI-64 process. -Beginning with Windows Vista, Windows uses a randomly generated interface ID instead of one created with EUI-64. Windows XP and previous Windows operating systems used EUI-64.

IPv6 Prefix Length

-In IPv6 it is only called the prefix length. IPv6 does not use the dotted-decimal subnet mask notation. Like IPv4, the prefix length is represented in slash notation and is used to indicate the network portion of an IPv6 address -A number, written as /x, where x is an integer between 0 and 128 inclusive, that defines the number of Primary bits in an IPv6 address, used for IPv6 subnetting and for matching with IPv6 ACLs.

Method 1: SLAAC

-In method 1, the router sends the first message, a multicast message, to all IPv6 nodes. -SLAAC is a method that allows a device to create its own GUA without the services of DHCPv6. -Using SLAAC, devices rely on the ICMPv6 RA messages of the local router to obtain the necessary information -By default, the RA message suggests that the receiving device use the information in the RA message to create its own IPv6 GUA and all other necessary information. The services of a DHCPv6 server are not required -SLAAC is stateless, which means there is no central server (for example, a stateful DHCPv6 server) allocating GUAs and keeping a list of devices and their addresses. With SLAAC, the client device uses the information in the RA message to create its own GUA. As shown in the figure, the two parts of the address are created as follows: Prefix - This is advertised in the RA message. Interface ID - This uses the EUI-64 process or by generating a random 64-bit number, depending on the device operating system.

Method 2: SLAAC and Stateless DHCPv6

-In this method PC send ICMPv6 to all IPv6 routers -A router interface can be configured to send a router advertisement using SLAAC and stateless DHCPv6. -As shown in the figure, with this method, the RA message suggests devices use the following: SLAAC to create its own IPv6 GUA The router LLA, which is the RA source IPv6 address, as the default gateway address A stateless DHCPv6 server to obtain other information such as a DNS server address and a domain name -A stateless DHCPv6 server distributes DNS server addresses and domain names. It does not allocate GUAs.

IPv6 routing

-RA messages are on IPv6 router Ethernet interfaces. The router must be enabled for IPv6 routing, which is not enabled by default. To enable a router as an IPv6 router, the ipv6 unicast-routing global configuration command must be used.

IPv6 subnet

-Recall that with IPv4, we must borrow bits from the host portion to create subnets. -However, IPv6 was designed with subnetting in mind. -A separate subnet ID field in the IPv6 GUA is used to create subnets -the subnet ID field is the area between the Global Routing Prefix and the interface ID. a 16-bit subnet ID - Creates up to 65,536 subnets. 64-bit interface ID - Supports up to 18 quintillion host IPv6 addresses per subnet (i.e., 18,000,000,000,000,000,000). -IPv6 subnetting is also easier to implement than IPv4 because there is no conversion to binary required. To determine the next available subnet, just count up in hexadecimal. -Only the subnet ID hextet is incremented in hexadecimal for each subnet

GUA dynamic addressing (RA/RS)

-The ICMPv6 RA message is a suggestion to a device on how to obtain an IPv6 GUA. The ultimate decision is up to the device operating system -For the GUA, a device obtains the address dynamically through Internet Control Message Protocol version 6 (ICMPv6) messages. -IPv6 routers periodically send out ICMPv6 RA messages, every 200 seconds, to all IPv6-enabled devices on the network. -An RA message will also be sent in response to a host sending an ICMPv6 RS message, which is a request for an RA message - RS messages are sent to all IPv6 routes requesting addressing information - RA is sent to all IPv6 nodes when method 1 (SLAAC) is used - RA includes Network prefix, Prefix-length, and Default-gateway information.

Routing table L

-The L indicates a Local route, the specific IPv6 address assigned to the interface. This is not an LLA. LLAs are not included in the routing table of the router because they are not routable addresses. -The IPv6 GUA configured on the interface is also installed in the routing table as a local route. The local route has a /128 prefix. -Local routes are used by the routing table to efficiently process packets with a destination address of the router interface address.

Ipv6 Ping

-The ping command for IPv6 is identical to the command used with IPv4, except that an IPv6 address is used. As shown in the example, the command is used to verify Layer 3 connectivity between R1 and PC1. When pinging an LLA from a router, Cisco IOS will prompt the user for the exit interface. Because the destination LLA can be on one or more of its links or networks, the router needs to know which interface to send the ping to.

FF02::2 All-routers multicast group

-This is a multicast group that all IPv6 routers join. -A router becomes a member of this group when it is enabled as an IPv6 router with the ipv6 unicast-routing global configuration command. -A packet sent to this group is received and processed by all IPv6 routers on the link or network.

ff02::1 All-nodes multicast group

-This is a multicast group that all IPv6-enabled devices join. -A packet sent to this group is received and processed by all IPv6 interfaces on the link or network. This has the same effect as a broadcast address in IPv4. -An IPv6 router sends ICMPv6 RA messages to the all-node multicast group.

Link-local

-This is required for every IPv6-enabled device -LLAs are used to communicate with other devices on the same local link -With IPv6, the term link refers to a subnet -LLAs are confined to a single link. -Their uniqueness must only be confirmed on that link because they are not routable beyond the link -In other words, routers will not forward packets with a link-local source or destination address

Routing table C

-Within the route table, a C next to a route indicates that this is a directly connected network. When the router interface is configured with a GUA and is in the "up/up" state, the IPv6 prefix and prefix length is added to the IPv6 routing table as a connected route. - i.e. 2001:DB8:ACAD:1::/64

show ipv6 route

-a command to show the IPv6 routing table -used to verify that IPv6 networks and specific IPv6 interface addresses have been installed in the IPv6 routing table -The show ipv6 route command will only display IPv6 networks, not IPv4 networks.

Unicast rule

-a source IPv6 address must be a unicast address -The destination IPv6 address can be either a unicast or a multicast address

Anycast

-address represents any one interface from a group of interfaces, any one of which can accept a transmission. -An IPv6 anycast address is any IPv6 unicast address that can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address

IPv6 Multicast Address

-all have the prefix FF00::/8. -Multicast addresses can only be destination addresses and not source addresses. -There are two types of IPv6 multicast addresses: Well-known multicast addresses Solicited node multicast addresses

Ipv6 unicast types

-global -link-local

unique local address

-range fc00::/7 to fdff::/7 -Unique local addresses are used for local addressing within a site or between a limited number of sites. -Unique local addresses can be used for devices that will never need to access another network. -Unique local addresses are not globally routed or translated to a global IPv6 address.

EUI-64 address

-stands for Extended Unique Identifier (EUI) -This process uses the 48-bit Ethernet MAC address of a client and inserts another 16 bits in the middle of the 48-bit MAC address to create a 64-bit interface ID. more specifically, -24-bit OUI from the client MAC address, but the 7th bit (the Universally/Locally (U/L) bit) is reversed. This means that if the 7th bit is a 0, it becomes a 1, and vice versa. -The inserted 16-bit value fffe (in hexadecimal). -24-bit Device Identifier from the client MAC address. -An easy way to identify that an address was probably created using EUI-64 is the fffe located in the middle of the interface ID. -The advantage of EUI-64 is that the Ethernet MAC address can be used to determine the interface ID -It also allows network administrators to easily track an IPv6 address to an end-device using the unique MAC address. However, this has caused privacy concerns among many users who worried that their packets could be traced to the actual physical computer. Due to these concerns, a randomly generated interface ID may be used instead.

Stateless vs Stateful

-stateful all the information is given but the default gateway. also, tracks addresses. (e.g., when an IPv4 DHCP server tracks the addresses that are given out) -Stateless DHCP does not track what information is given out to clients and does not give out IPv6 addresses. Gives DNS address. By the way, SLAAC alone is also stateless. meaning it does not allocate DHCPv6 addresses and keep track of them.

Rule 1 - Omit Leading Zeros

01ab can be represented as 1ab 09f0 can be represented as 9f0 0a00 can be represented as a00 00ab can be represented as ab -This rule only applies to leading 0s, NOT to trailing 0s, otherwise, the address would be ambiguous. For example, the hextet "abc" could be either "0abc" or "abc0", but these do not represent the same value.

Translation (TS Protocol)

Network Address Translation 64 (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4. An IPv6 packet is translated to an IPv4 packet and an IPv4 packet is translated to an IPv6 packet.

Unicast

An IPv6 unicast address uniquely identifies an interface on an IPv6-enabled device.

Dual stack (TS Protocol)

Dual stack allows IPv4 and IPv6 to coexist on the same network segment. Dual stack devices run both IPv4 and IPv6 protocol stacks simultaneously. Known as 1pv6

Eathernet MAC address

Ethernet MAC addresses are usually represented in hexadecimal and are made up of two parts: Organizationally Unique Identifier (OUI) - The OUI is a 24-bit (6 hexadecimal digits) vendor code assigned by IEEE. Device Identifier - The device identifier is a unique 24-bit (6 hexadecimal digits) value within a common OUI.

All 0 and 1 (Ipv6)

IPv4, in IPv6, the all-0s and all-1s host addresses can be assigned to a device. The all-1s address can be used because broadcast addresses are not used within IPv6. The all-0s address can also be used, but is reserved as a Subnet-Router anycast address, and should be assigned only to routers

/64

It is strongly recommended to use a 64-bit Interface ID for most networks. This is because stateless address autoconfiguration (SLAAC) uses 64 bits for the Interface ID. It also makes subnetting easier to create and manage

NAT problems

NAT is problematic for many applications, creates latency, and has limitations that severely impede peer-to-peer communications

RFC 1918 (ipv4)

RFC 1918 defines the following address ranges as private, 10.0. 0.0/8 (addresses 10.0. 0.0 through 10.255. 255.255 inclusive) 172.16. 0.0/12 (addresses 172.16. 0.0 through 172.31. 255.255 inclusive) 192.168. 0.0/16 (addresses 192.168. 0.0 through 192.168.

Global unicast

Similar to a 'public' IPv4 address -Globally unique -Internet routable addresses -Can be configured statically or assigned dynamically -equivalent to public IPv4 addresses -Currently, only GUAs with the first three bits of 001 or 2000::/3 are being assigned -GUAs have 3 parts, 1. a /48 Global Routing prefix 2. 16-bit subnet ID 3. 64-bit Interface ID

RA message contains

The ICMPv6 RA message includes the following: Network prefix and prefix length - This tells the device which network it belongs to. Default gateway address - This is an IPv6 LLA, the source IPv6 address of the RA message. DNS addresses and domain name - These are the addresses of DNS servers and a domain name.

RA msg

The ICMPv6 RA message is a suggestion to a device on how to obtain an IPv6 GUA

Transition Company

The IETF has created various protocols and tools to help network administrators migrate their networks to IPv6

Private Ipv6 address

They are unicast addresses, but contain a 40-bit random number in the routing prefix to prevent collisions when two private networks are interconnected. Despite being inherently local in usage, the IPv6 address scope of unique local addresses is global.

Tunneling (TS Protocol)

Tunneling is a method of transporting an IPv6 packet over an IPv4 network. The IPv6 packet is encapsulated inside an IPv4 packet, similar to other types of data.

IPv6 all-nodes

Unlike IPv4, IPv6 does not have a broadcast address. However, there is an IPv6 all-nodes multicast address that essentially gives the same result.

Device Address Assignment (IPv4)

Within a network, there are different types of devices that require addresses: End user clients - Most networks allocate IPv4 addresses to client devices dynamically, using Dynamic Host Configuration Protocol (DHCP). This reduces the burden on network support staff and virtually eliminates entry errors. With DHCP, addresses are only leased for a period of time, and can be reused when the lease expires. This is an important feature for networks that support transient users and wireless devices. Changing the subnetting scheme means that the DHCP server needs to be reconfigured, and the clients must renew their IPv4 addresses. IPv6 clients can obtain address information using DHCPv6 or SLAAC. Servers and peripherals - These should have a predictable static IP address. Use a consistent numbering system for these devices. Servers that are accessible from the internet - Servers that need to be publicly available on the internet must have a public IPv4 address, most often accessed using NAT. In some organizations, internal servers (not publicly available) must be made available to the remote users. In most cases, these servers are assigned private addresses internally, and the user is required to create a virtual private network (VPN) connection to access the server. This has the same effect as if the user is accessing the server from a host within the intranet. Intermediary devices - These devices are assigned addresses for network management, monitoring, and security. Because we must know how to communicate with intermediary devices, they should have predictable, statically assigned addresses. Gateway - Routers and firewall devices have an IP address assigned to each interface which serves as the gateway for the hosts in that network. Typically, the router interface uses either the lowest or highest address in the network.

ICMPv6 contains

address resolution and address autoconfiguration, not found in ICMP for IPv4

run out of address

four out of the five RIRs have run out of IPv4 addresses (afrinic is left)