Questions tagged [ipv6]

For questions about Internet Protocol version 6 (IPv6); as specified in RFC2460.

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3
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1answer
397 views

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router?

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router? I know that they all join these two groups: all multicast nodes and all ...
8
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2answers
10k views

Why don't we use MAC address instead of IP for having “Internet” or doing communication? [duplicate]

We know MAC address is unique in each devices.So why can't we just send/receive data using MAC address only?
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1answer
917 views

DNS64/NAT64 WiFi hotspot using Windows [closed]

Is there a way to have this option proposed by Apple available in Windows? I want to test connecting an IPv6-only client to an IPv4-only server on a local environment.
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1answer
77 views

How to get the IPv6 [closed]

I'm in a network that provides both IPv4 and IPv6 for the nodes, and i have the IPv4 of a machine. How can I find the IPv6 assigned for this machine?
1
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1answer
202 views

Checking split horizon status with IPv6

In a frame relay multipoint topology where the routers are running RIP, we know that RIP by default keeps split horizon on with IPv6 and we go into the RIP process an use no ip-split horizon to ...
3
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2answers
241 views

IPv6 tunneling over IPv4

I am willing to build a program that simulates the routing process of IPv6 packets over an IPv4 overlay network (tunnel). From what I have read so far I have understood that the IPv4 tunnel packets ...
1
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1answer
2k views

Calculate networking bits for IPv6

I can get the networking bits for IPv4 addresses like 17 for 255.255.128.0. Similarly, how should I calculate it for IPv6 addresses? Say, if I have a subnet mask of ffff:ffff:ffff:ffff:0:0:0:0 or ...
3
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2answers
147 views

Switching to public IPv6

I'm considering the possibility of moving my public addresses to IPv6 for several web applications and sites that I host. When inquiring with my ISP, the account exec replied to me with the following ...
4
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1answer
533 views

Network Diagram for IPv6 LAN

From what I understand about IPv6 networks, since NAT was a hack to deal with a lack of IP addresses in IPv4, NAT is a possibility, but not a requirement in an IPv6 LAN. So taking this into account,...
1
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2answers
533 views

IPv6: is it possible to use a /64 block when you have multiple routers?

I'm new to IPv6 and having some issues with a configuration that was really easy/common with IPv4. My setup looks like this: WAN (ISP managed router) <-> Router 1 ( my internal router ) <-&...
4
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2answers
5k views

IPv6 ULA vs Link-Local

Could some one kindly explain what is the difference between IPv6 Unique Local Addressing and Link-Local addressing? I understand that Link-Local is for within a network, but isn't Unique Local ...
2
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3answers
4k views

IPv6 addressing (slash notation)

I've recently been studying the fundamentals on IPv6, but there are some things that I don't quite understand about how the addressing is structured. I know that link local addresses start with FE80, ...
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1answer
47 views

What is the command line to inspect the IPv6 discovery cache?

I can't seem to find a command for this, only configuration commands are listed in the documentation and show ipv6 nd destination does not work on my system This is on Cisco vIOS 15.2 Edit: ...
2
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1answer
138 views

Is the structure of the CEF IPv6 trie similar with the IPv4 trie structure?

Is the structure of IPv6 mtree similar with the IPv4 mtree structure? Have you guys seen any documentation about this subject?
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2answers
1k views

Why is Cisco enforcing X:X:X:X::X for link-local addresses when the standard says FE80:/10?

This document shows that you can use one of these options: interface type/number ipv6 address ipv6-prefix/prefix-length eui-64 ipv6 address ipv6-prefix/prefix-length link-local <------...
7
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1answer
2k views

Why is the NDP Neighbor Solicitation message sent to the solicited-node address?

As I understand it, when Host Alice knows Host Bob's IPv6 address but not its MAC, Alice sends an NDP Neighbor Solicitation (NS) message to the solicited-node multicast address for Bob. Alice knows ...
3
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1answer
508 views

Is there any way to check if an IP address is a real IP address or private IP address?

Is there any way to check if an IP address is a real IP address or private IP address?
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1answer
84 views

Which fields in the IPv6 header are checked during an IP lookup?

I'll consider IPv6 headers for this question. I assume that the simplest IP lookup scheme implementation would just look at the 'Destination Address' field in the IP header of an incoming IP packet. ...
1
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1answer
250 views

Proper way to use IPv6 address range

I have the following IPv6 addresses range, with netmask 64 : A:B:C:D:E:0000:0000:0000 -> A:B:C:D:E:0000:0000:FFFF I have to assign some of them to virtual machines. Should I use A:B:C:D:E:0000:0000:...
4
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3answers
3k views

Usage of Flow label in IPv6 header?

I have been reading the IPv6 Flow Label Specification (RFC 6437) and I would like to ask about the purpose of setting this label. In case of just using the 2-tuple (source address, destination ...
2
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1answer
1k views

IPv6 Subnetting

I was making an IPv6 exercise in which I had to configure two Router Interface: G0/0 and G0/1 G0/0 uses 2001:DB8:FADE:00FF::/64 and I have to use to next subnet for G0/1 This is the answer, but What ...
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1answer
65 views

IPv6 address abbreviateion

Given IPv6 address 2001:0000:0000:0000:1111:0000:0000:0000, should it be abbreviated as: 2001::1111:0:0:0 or 2001:0:0:0:1111::? It seems I didn't see any specification talking about it.
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1answer
1k views

What happened to IPv5?

I hear/read much about IPv4 and IPv6 and nothing about IPv5. Where did it get lost in the discussion?
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1answer
214 views

How much influence does multicast and IPv6 have on latency?

I am looking for a fast and a diverse library for my game engine network. I have searched for a while, and I decided to use a simple one because of being fast to understand. I saw there are better ...
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3answers
3k views

IPv6 NAT with Link-Local Address

It's more than usual to find NAT translating IPv4 private addresses (such as 192.168.0.0/16 or 10.0.0.0/8) to non private addresses. Is it possible that NAT translates even IPv6 link-local addresses (...
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2answers
243 views

Are there limits to the number of global IPv6 multicast addresses in use at a time?

The address space for IPv6 multicast addresses is very large (something like 2^112) and so I'm imagining it might not be so hard to get my hands on a million or so of them at some point, and try using ...
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2answers
2k views

pfSense: ICMP Ping allowed, but not possible

I have a pfSense 2.2.6 box that is connected with a WAN link that supports native IPv6. IPv6 is working great, and my clients can access IPv6 services on the Internet and also on the local network. ...
5
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2answers
156 views

IPv6 built-in security?

At one time IPv6 was supposed to have built-in security. I don't know how it was supposed to be implemented, but my guess is that perhaps, if your stack and application supported it, you could simply ...
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2answers
431 views

What is the proper name for hexadecimal like standard notation of an IPv6 address?

RFCs such as 5952 - "A Recommendation for IPv6 Address Text Representation" and 2373 - "IP Version 6 Addressing Architecture" each outline the commonly used hexadecimal and colon based notation that ...
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1answer
179 views

How to verify whether two devices can communicate

In IPv4, we had to find the Network Address using the IP address and the subnet mask. With IPv6 there's already the Network Prefix in the IP address. Suppose I have an IP address A: 2001:db8:a0b:12f0::...
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2answers
1k views

Converting IPv6 to Dotted Decimal Notation [closed]

Does anyone have a simple way to convert IPv6 addresses to dotted decimal notation? I am currently using a pretty ugly python script which: Converts the IPv6 address to exploded form Splits every ...
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1answer
2k views

MAC address can be used to generate an IPv6 link local address

MAC address can be used to generate an IPv6 link local address. What is the process of using MAC address to derive an IPv6 address ? What are the problems that can be caused due to process of using ...
3
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1answer
346 views

Why is space reserved for private ip addresses?

I just read that specific ranges of IPs have been set aside to be used to private ip addressing. But if we already distinguish between public and private IPs why do we need to reserve space? Why cant ...
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1answer
80 views

Is IPv6 Routing Header useless?

RFC2460 doesn't describe any types other than Type 0. And in RFC5095, it deprecated Type 0 Routing Header. Does that mean Routing Header is useless?
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1answer
113 views

What does the Flow mean?

Above image explains how to communicate between IPv4 and IPv6 by tunneling.. I understand that concept by wrapping IPv6 datagram into iPv4 datagram.. But I do not understand what the 'Flow X' in the ...
4
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1answer
721 views

6to4 - IPv6 tunnel address

http://packetlife.net/blog/2010/mar/15/6to4-ipv6-tunneling/ In order to configure a 6to4 tunnel on R2 router, you execute the following commands: R2(config)# interface tunnel0 R2(config-if)# tunnel ...
3
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1answer
458 views

IPv6 6to4 mechanism

I'm not sure if I get the idea of 6to4 mechanism. The way I see it: if we have two IP v6 hosts that would like to communicate and all of the internet was IP v6, there would be no problem. However, ...
2
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2answers
152 views

Broadcasts in IPv6

I'm aware of the fact that broadcast has been removed from IPv6 and just has multicast instead. However, recently I read "This process (ARP) is now achieved via a multicast address called the ...
10
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3answers
20k views

What is Link-local addressing?

I noticed that IPv4 reserved 169.254.0.0/16 and IPv6 reserved fe80::/10 for link-local addressing. While I saw IPv6 uses both fe80::/10 address and my private IPv6 address fd00::12 to communicate with ...
4
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1answer
525 views

TCAM entry width

if IPv4 is 32 bits and IPv6 is 128 bits wide, why TCAM is configured to be 36, 72, or 144 bits wide? why don't configure it as 32, 64, and 128 bits? if there is link for reading material would be ...
44
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5answers
8k views

Why do we need IPv6?

This will be a kind of newbie question but I am not quite sure why we really need IPv6. AFAIK, the story is as follows: In the olden days, when computers were not plentiful, 32 bit IP addresses were ...
3
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1answer
3k views

Understanding the difference between EUI-64 and IPv6

I understand that Extended Unique Identifier (EUI-64) allows a host to automatically assign itself a 64-bit interface identifier IID for an IPv6 address. My question is: What is the purpose of using ...
1
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2answers
693 views

NAT translation of a packet on interface with IPv4 address to interface with IPv6 address and vice versa

I have two interfaces on my linux machine, lets say eth0 and eth1. eth0 is a public IP that has IPv6 address and eth1 has a private IPv4 address. If I try to nat the packets that received on eth1 ...
2
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1answer
313 views

Why is only 24 bits of the MAC address used for multicasting?

When doing neighbor discovery in IPv6, the last 24 bits of the hosts MAC address is glued on to some link local multicast prefix. I'm wondering why 24 bits? Why not 48, or 32, or 16? What happens if ...
2
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1answer
83 views

Mobile Node home address and Mobile Node Home Agent Address

I have been reading mobile IPv6 for a while and in that the two terms: Mobile Node's Home address and Mobile Node's Home agent address are used frequently, and they seem similar to me. My ...
2
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1answer
51 views

The length of Fragment header in IPv6

From RFC2460 :https://tools.ietf.org/html/rfc2460#section-4.5, the length of the fragment header seems to be fixed 8 bytes. But when I test with Scapy with the default fragment header, from sniffer ...
3
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5answers
266 views

Since we ran out of IPv4 now, what does it mean for consumers?

I'm trying to understand what it means for users... Does it mean that some content will not load on websites, increasingly so in the upcoming year or so? Does it mean that certain CDNs or hostings ...
2
votes
1answer
80 views

Parse the Encapsulating Security Payload

RFC2460 defines some extension headers, like hop-by-hop, Routing Options...etc. All these headers seem to have the next header type and header extension length in the beginning of the header. However ...
7
votes
1answer
4k views

Smallest IPv6 block advertised?

We've received a /48 allocation from ARIN, and want to advertise smaller blocks from different sites in our organization. I tried advertising a /56 from each site, but ISP is telling me they won't ...
1
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0answers
59 views

IPv6 network addresses with 6to4 router and tunnel [closed]

I'm currently studying for an upcomming exam and I came across the following question, the IP-Addresses are to be filled in by me and this is my try at solving it, but I'm not sure if the IP-Address, ...