Questions tagged [ipv6]

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

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1answer
32 views

Next Header field in IPv6 vs Protocol field in IPv4, any difference?

So I am new to the IPv6 concept, and I seen that the Protocol field seems to be replaced with Next Header, and I have a question. Question: Is Next Header a complete replace of Protocol, or is they ...
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4answers
59 views

Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address?

This is a follow-up question to Why is the NDP Neighbor Solicitation message sent to the solicited-node address?. Summary: say I would send an IPv6 packet and put the unicast address of the host I ...
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1answer
48 views

Fortigate and ipv6 routing

I have a Fortigate router and my ISP support ipv6. I'm getting a public ipv6 on the Fortigate and also on the computers on the lan (2a02:a18:9041....) I have not to much understanding of ipv6, but by ...
3
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1answer
62 views

Global Unicast in IPv6 Neighbor Discovery

I have a very small pcap file in which Neighbor Discovery is performed for Global Unicast Addresses. That is, IPv6 addresses of both neighbors as I can see in Wireshark start from 2001:. Both IPv6 ...
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2answers
376 views

Link Local Address using in NDP (IPv6)

How is using of link local address in NDP. We can discover neighbor by using global address. So why we need link local address in NDP?
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1answer
59 views

Confusion about IANA “Protocol Numbers” registery

In the IANA registery for "Protocol Numbers", there listed 2 IP protocol versions: IPv4 at #4 and IPv6 at #41. Their "protocol" column says IPv[46] Encapsulation, and "reference" column points to 2 ...
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1answer
24 views

Does network layer provide connection oriented service

I know that in TCP/IP model the data link layer provides connection less service. While reading IPv6 Header. 'The flow label is used for connection oriented servie'. How does TCP/IP model provide ...
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1answer
36 views

Function of the P-bit flag in an IPv6 multicast

Currently I'm trying to learn (common) things about IPv6 and started with the address format and the address scopes. Finally I reached the multicast part where my problem with the definiton of the ...
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2answers
68 views

Is the first address in an IPv6 subnet assignable?

I am working in a lab and have configured a series of /125 subnets between routers. Lets ignore the best practice for this discussion of using /64 for everything. When I assign fd00:f9a8:ffff::257 to ...
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1answer
45 views

Understanding EUI-64

I was reading Forouzan's book. It says following: In IPv4 addressing, there is not a specific relation between the hostid (at the IP level) and link-layer address (at the data-link layer) because ...
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1answer
60 views

configure IPv6 ACL on interface WS-C3750X-48

I am using  WS-C3750X-48 model switch. license is lanbase. I have activated cmd on my switch: sdm prefer dual-ipv4-and-ipv6 routing. Then i did reload. After that, i will able to config IPv6 on ...
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2answers
236 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 ...
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2answers
2k views

Why the first octet of a MAC address always end with a binary 0?

I stumbled upon a piece of code on GitHub: https://github.com/adeverteuil/bash-ula-generator/blob/master/gen-ula.sh # Generate an EUI64 from the MAC address # as described in RFC 3513 # https://tools....
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2answers
65 views

Why is the IPv6 link-local address not /9?

According to this answer, it's because computers read addresses in binary. Fine. That explains why the fe80 address does not need to be /12 or /16--it's because everything after the 10th bit is a ...
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2answers
5k views

pfSense IPv6 NAT

I know many of you said that IPv6 has no NAT, but my server provider told me, that it is possible. I have no idea how... I have a pfSense Server as my Firewall (Not the router!). I have a /28 IPv4 ...
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2answers
7k views

Is it true that the fd00::/8 address range (ULA) in ipv6 is for machines that you NEVER want to speak with anything on the Internet?

Is it true that the fd00::/8 address space (User Local Addresses) in ipv6 is for machines that you NEVER want to speak with anything on the Internet? I was just reading that here and rather surprised ...
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3answers
76 views

Do extension headers in IPv6 increase the header length

I was reading about IPv6. It says the header is of a fixed size i.e. 40 bytes, then how come is it able to accommodate extension headers. Doesn't this alter the size of headers. Please help, cant ...
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3answers
150 views

How to do subnetting on IPV6 for non nibble boundaries?

As I was reading this article on How to: calculating IPv6 subnets outside the nibble boundary https://blog.apnic.net/2018/08/10/how-to-calculating-ipv6-subnets-outside-the-nibble-boundary/ The author ...
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0answers
17 views

What is meant by “IP fragmentation is done on a 8-byte boundary”? [duplicate]

I was learning about IPv4 fragmentation and came across the follwoing line: The data of the long packet is then divided into two portions on a 8 byte (64 bit) boundary, so that the first packet ...
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1answer
180 views

What does NAT64 do which can't be done by deploying IPv6 + NAT444?

Why was NAT64 developed? What does it do that can't be done by deploying IPv6 + NAT444, and allocating your customers a (public) IPv6 and a (private) IPv4 address (behind a shared public IPv4 address)?...
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0answers
34 views

How to route dynamic PPPoE prefix delegated IPv6 prefixes to a layer 3 switch on IOS XE

Network setup: IOS XE 16.x --> Cisco 3560G layer 3 switch --> clients The IOS XE device does PPPoE dialing to our ISP and runs some VPNs to other sites. The 3560G does inter-VLAN routing and ...
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1answer
25 views

How to assign an ipv6 address to router 2900 gigabitethernet 0/0/0 - 0/0/3 interfaces?

I am working with a cisco router model 2900 which has four gigabitethernet 0/0/0 - 0/0/3. They do accept ipv4 addresses, however they will not accept ipv6 address. I have tried to use svi (assigning ...
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3answers
64 views

Can u explain this representation of the IPv6 address 1001::1 64?

::1 is for loopback address. An IPv6 address contains 8 16-bit pieces. What do this representation 1001::1 64 mean (what is the full address with all 8 16-bit pieces)?
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1answer
45 views

Packet Tracer 7.2.1 does not support eigrp for ipv6

I'm trying to enable eigrp for ipv6 in packet tracer but is seems to only have ospf and rip for ipv6. Is this a recent limitation?
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0answers
19 views

Can a Neighbor Advertisement response packet trigger the transition from STALE to DELAY?

I think the title is pretty descriptive. I cannot seem to find anything in the standard about what kind of packets could trigger the transition from the state STALE to the state DELAY, in the ...
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1answer
46 views

How much of an IPv6 address should be considered a single “identity” when counting votes [closed]

I'm building a web platform that uses upvotes and downvotes on each piece of content to bring good content to the top. It's important that it's non-trivial for this voting to be rigged, and previously ...
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1answer
55 views

Ping error ipv6

I am able to ping a PC1 to R1, Pc2 to r2 and PC3 to R3. All routers can ping each other. PC's can also ping themselves but I can't ping different PC's, I also cannot ping a PC to their own Gateway. ...
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1answer
45 views

Remote Host Neighbor Cache Entry State after Neighbor Solicitation request

When a Host A sends for the first time a NS request to another Host B, host B answers with a NA. In Host A Neighbor Cache, the state Entry for host B gets from INCOMPLETE to REACHABLE, when NA comes ...
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1answer
39 views

Assign a new public and static IP to a router behind my main router [closed]

What can you suggest to bring a second public and static IPv4 so I can configure my WAN-A interfase with my primary and an additional secondary IP settings so I can route all the traffic from the ...
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2answers
44k views

Stateful vs Stateless IPv6?

What's the difference here? Are stateful IPv6 entries retained in the DHCPv6 server?
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4answers
8k views

Why is the U/L bit inversed in EUI64?

This inversion is bijective, so I can't figure out what is it's use.
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1answer
57 views

RDP on IPV6 using DS-Lite-Tunnel [closed]

I am trying to access one of my PCs from and external network using RDP on port 3389. After realizing my ISP uses DS-Lite-Tunnel I gave up ipv4 and focusing on ipv6. So far the only way I managed ...
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1answer
23 views

How to group 3 hosts in ACE Ipv6 statement

I know for ipv6 ACE there is no wildcard mask, so if I want to add three hosts in one statement, for example, which prefix should I use for that network? (network 2001:db8:cafe:1/64, ::1 reserved as ...
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6answers
4k views

Could IPv6 make NAT / port numbers redundant?

From what I can tell, each process could get its own IP address, with loads of IP's to spare. What would the drawbacks be? Essentially, your host would become a router and each process is a host (in ...
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1answer
136 views

Setting Destination MAC address for RTP/UDP packets

I have a requirement where I have to send the UDP packet to a destination multicast IPv6 address. In addition to that the packets must also have corresponding destination multicast MAC address set. I ...
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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 ...
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4answers
10k views

What is the proper term for ipaddress/hostname:port

What is the proper term for (example) hostname.tld:433 (hostname:portnumber)? It is not just hostname, and it is not really a URL either :) same goes for 10.0.0.1:3306 etc.
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1answer
68 views

Does CSR1000v on AWS support IPv6?

I'm trying to implement Segment Routing IPv6 (SRv6) in Cisco CSR1000v on AWS. I'm having issues with IPv6 which gave the impression that IPv6 data plane does not work. Similarly, I configured a ...
3
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1answer
42 views

How to handle IPv6 Extension Header Options with action = 01

RFC 8200 section 4.2 states that if a node does not recognize an option type, that node must do some action depending on the 2 higher order bits of the option type. When the higher order bits are 01, ...
2
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2answers
80 views

How to handle ICMP-in-IPv6 or ICMPv6-in-IPv4?

Since ICMP and ICMPv6 have different IP protocol numbers, it's technically possible for an IPv4 host to receive an ICMPv6 packet or for an IPv6 host to receive an ICMP packet. Is the host's behavior ...
6
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1answer
90 views

How to set IPv6 RA values for RDNSS and DNSSL on HPE/Aruba 5400R

I am detail-planning the roll out of IPv6 in our company. Right now I am stuck with IPv6 RA on our HPE/Aruba Access Switches. I cannot find any documentation how to set the Recursive DNS Server (RDNSS)...
2
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1answer
76 views

ipv6 dhcp pool option link-address

I'm learning to set up an ipv6 dhcp pool in Packet Tracer. And I'm stomped on what a link-address is as an option in a dhcp server ipv6. I've read this https://www.cisco.com/c/en/us/td/docs/ios-xml/...
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2answers
169 views

How to architect a globally distributed website, from an IP address perspective

I would like to have a website that is loaded fast from any point in the world. From my understanding, you need to take advantage of the data center "regions" at places like Google Cloud or AWS. That'...
2
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0answers
51 views

RPL: questions on routing mechanism

I'm studying RPL and two questions came to my mind: 1: Both in storing and non-storing modes, if a node wants to send a packet to another node via P2P communication paradigm, then how does the ...
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4answers
14k views

IPv6: Why not use /126 on P2P links for IPv6?

In IPv4 we use /30 to conserve addresses. So why do some people recommend using /64 on P2P links instead of /126? I get using a /64 on regular subnets but isn't using a /64 when there will only ever ...
4
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1answer
341 views

IPv6 default route not being installed from RA

Platform: Juniper SRX300 Version: JUNOS 15.1X49-D160.2 ISP: Midco I currently have an issue where the IPv6 default route is not being installed from the CMTS RA. Try as I might, I cannot get ...
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2answers
778 views

Does IPv6 have similar concept of network mask?

Does IPv6 have similar concept of network mask? How does it represent a network? In the output of ifconfig, does prefixlen 128 represent a network mask? lo: flags=73<UP,LOOPBACK,RUNNING> mtu ...
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2answers
1k views

Why do IPv6 unique local addresses have to have a /48 prefix?

According to RFC 4193, unique local addresses will always have a prefix of FD00::/8.. but according to Wikipedia: The block fd00::/8 is defined for /48 prefixes, formed by setting the forty least-...
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3answers
1k views

Are the IPv6 address space and IPv4 address space completely disjoint?

Tanenbaum's Computer Networks says Finally, IPv4 addresses can be written as a pair of colons and an old dotted decimal number, for example: ::192.31.20.46 Does it mean the IPv4 address space ...
2
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1answer
52 views

What can an IP address be assigned to?

What can an IP address be assigned to? A network interface, which is what I thought originally. (I seem to hear a network interface can have multiple IP addresses assigned to it, and if it is true, ...