{"id":857,"date":"2021-08-20T03:07:44","date_gmt":"2021-08-20T03:07:44","guid":{"rendered":"http:\/\/feralpacket.org\/?p=857"},"modified":"2021-08-20T03:07:44","modified_gmt":"2021-08-20T03:07:44","slug":"ipv6-notes","status":"publish","type":"post","link":"https:\/\/feralpacket.org\/?p=857","title":{"rendered":"IPv6 Notes"},"content":{"rendered":"

IPv6<\/span><\/p>\n

 – 128 bit address represented in HEX format<\/p>\n

     -> 1 hex = 4 bits<\/p>\n

     -> 32 HEX numbers = 1 IPv6 address<\/p>\n

 – 8 quartets (16-bit blocks) or 4 HEX numbers each<\/p>\n

12CD:0000:0000:0000:0635:0000:0000:0001 \/64<\/p>\n

If a quartet has all zeros, it can be replaced with a single zero<\/p>\n

12CD:0:0:0:0635:0:0:001 \/64<\/p>\n

Leading zeros in a quartet can be dropped<\/p>\n

12CD:0:0:0:635:0:0:1 \/64<\/p>\n

Consecutive quartets of zeros can be replaced with a double colon (::) once<\/p>\n

12CD::635:0:0:1 \/64<\/p>\n

Unicast<\/span><\/p>\n

 – Globally unique (public IPs<\/p>\n

 – Range – 2000:: \/3<\/p>\n

 – 001x -> first 3 bits will always be the same<\/p>\n

 – Will always start with 2 or 3<\/p>\n

     -> 0010 – 2<\/p>\n

     -> 0011 – 3<\/p>\n

local-link addresses<\/span><\/p>\n

 – Automatically assigned<\/p>\n

     -> scope is link-local<\/p>\n

 – Any interface that has IPv6 activated will have a link-local address<\/p>\n

     -> Can be changed<\/p>\n

 – Range – FE80:: \/10<\/p>\n

Multicast<\/span><\/p>\n

 – Range – FF00:: \/8<\/p>\n

 – The fourth HEX character in the first quartet is called the scope field<\/p>\n

     -> 2 – scope is link-local<\/p>\n

     -> 5 – scope is site-local<\/p>\n

     -> E – scope is global<\/p>\n

          -> FF0E:: \/16 – used on the Internet<\/p>\n

Well known multicast addresses<\/span><\/p>\n

 – FF02::1 -> all nodes in the segment<\/p>\n

 – FF02::2 -> all routers in the segment<\/p>\n

 – FF02::5 -> OSPF all routers<\/p>\n

 – FF02::6 -> OSPF all DRs<\/p>\n

 – FF02::9 -> RIPng<\/p>\n

 – FF02::A -> EIGRPv6<\/p>\n

 – FF05::1:2 -> DHCPv6<\/p>\n

 – FF02::1:FF00:0000 \/104 -> Solicit Node Multicast Address<\/p>\n

     -> first 104 bits stay the same<\/p>\n

          -> FF02::1:FF<\/p>\n

     -> last 24 bits can change<\/p>\n

          -> 00:0000<\/p>\n

<\/p>\n

Anycast<\/span><\/p>\n

 – One – to – one of many<\/p>\n

 – Any IPv6 address can be flagged as Anycast<\/p>\n

IPv6 Address Assignment<\/span><\/p>\n

int fa0\/0<\/span><\/p>\n

 ipv6 enable<\/span><\/p>\n

     -> Causes a link-local address to be generated<\/p>\n

 ipv6 address <ipv6 add>\/<network mask><\/span><\/p>\n

     -> Manual addressing<\/p>\n

 ipv6 address dhcp<\/span><\/p>\n

     -> Receive address from DHCPv6 server<\/p>\n

 ipv6 address <\/span>x:x:x:x::<\/a> \/64 eui-64<\/span><\/p>\n

     -> EUI-64 method<\/p>\n

 ipv6 address autoconfig<\/span><\/p>\n

     -> Autoconfiguration<\/p>\n

EUI-64 Method<\/p>\n

 – last 64 bits (host part) id derived from the MAC address of the interface<\/p>\n

     -> MAC address -> 48 bits<\/p>\n

     -> FFFE -> inserted in the middle of the MAC address<\/p>\n

     -> The 7th bit is then flipped<\/p>\n

     -> The 7th bit is called the global \/ local bit<\/p>\n

0001.0002.0003 plus FFEE<\/p>\n

 – Becomes<\/p>\n

     -> 0001.00FF.FE02.0003<\/p>\n

0001 in HEX<\/p>\n

 – 0000000000000001 in decimal<\/p>\n

7th bit flipped<\/p>\n

 – 0000001000000001 in decimal<\/p>\n

 – 0201 in HEX<\/p>\n

So, 0001.0002.0003 plus FFFE plus 7th bit flipped becomes<\/p>\n

 – 0201.00FF.FE02.0003<\/p>\n

     -> host part of the EUI-64 address<\/p>\n

<\/p>\n

Autoconfiguration<\/span><\/p>\n

R2(config)# int fa0\/0<\/span><\/p>\n

 ipv6 enable<\/span><\/p>\n

 ipv6 address autoconfig<\/span><\/p>\n

     -> Receiving side<\/p>\n

     -> Uses EUI-64<\/p>\n

R1 sends periodic Router Advertisement (RA) messages<\/p>\n

 – Clients can also request an address by sending Router Solicitaion (RS) messages<\/p>\n

 – RA contains the first 64 bits of router’s address<\/p>\n

     -> FC01:2:3:4 in this case<\/p>\n

 – When the client receives the RA message, it uses the 64 bits in the message as the network part and calculates the host 64 bits by using the EUI-64 method<\/p>\n

RA \/ RS messages<\/p>\n

 – Part of the family of ICMPv6<\/p>\n

<\/p>\n

By default, RA messages are suppressed on serial interfaces<\/p>\n

R1(config)# int s0\/0<\/span><\/p>\n

 no ipv6 nd ra suppress<\/span><\/p>\n

R2(config)# int s0\/0<\/span><\/p>\n

 ipv6 enable<\/span><\/p>\n

 ipv6 address autoconfig<\/span><\/p>\n

Serial interfaces don’t have MAC addresses<\/p>\n

 – Autoconfig on a serial interface will use (borrow) the MAC address of an ethernet interface on the router<\/p>\n

<\/p>\n

IPv6 Neighbor Discovery (ARP)<\/span><\/p>\n

 – NS -> Neighbor Solicitation<\/p>\n

 – NA -> Neighbor Advertisement<\/p>\n

FF02::1 -> all nodes<\/p>\n

Solicite Node Multicast group is joined by every IPv6 enabled device<\/p>\n

FF02::1:FF00:0000 \/104<\/p>\n

     -> Last 24 bits are taken from IPv6 address of the device<\/p>\n

2000:0:0:0:0:0:0:1<\/p>\n

     -> Last 24 bits – 00:0001<\/p>\n

The multicast group the computer will join<\/p>\n

     -> FF02::1:FF:00:001 – Computer A<\/p>\n

     -> FF02::1:FF:00:002 – Computer B<\/p>\n

     -> FF02::1:FF:00:003 – Computer C<\/p>\n

     -> FF02::1:FF:00:004 – Computer D<\/p>\n

Computer1> ping 2001::3<\/p>\n

 – Computer sends a NS message to the Solicit Node Multicast addressed generated by the last 24 bits of the destinations IP address<\/p>\n

 – The receiving computer responds back with a unicast NA message which contains the MAC address<\/p>\n

Duplicate Address Detection (DAD)<\/span><\/p>\n

 – Devices send NS to the multicast group that itself has joined asking for it’s own IPv6 address<\/p>\n

 – If anyone else replies, then there is a conflict<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0– 128 bit address represented in HEX format<\/p>\n","protected":false},"author":1,"featured_media":853,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[40,31],"class_list":["post-857","post","type-post","status-publish","format-standard","hentry","category-ccie","tag-ipv6","tag-published"],"_links":{"self":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=857"}],"version-history":[{"count":1,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/857\/revisions"}],"predecessor-version":[{"id":966,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/857\/revisions\/966"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/media\/853"}],"wp:attachment":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=857"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=857"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}