Questions tagged [ipv6]

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

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How HTTP is converted to TCP and then how TCP converted to IP?

I know that in Internet Protocol Stack there are actually three layer. They are Application, Internet and Transport. Let's say HTTP in Application layer will be converted to TCP in Transport layer and ...
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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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Is there an Assignment Window (AW) for IPv6 in the RIPE region?

In IPv4, newborn LIRs must seek approval from the RIPE NCC before assigning a prefix larger than a certain size to end users. As time goes (and RIPE see that you fill in the RIPE database correctly),...
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Does IPv6 remove the need for a VPN?

I know that a VPN may be used in lots of different ways for lots of different things, so I'm not suggesting that IPv6 removes the need for a VPN completely. I'm interested in one particular use-case: ...
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Is the first address of the subnet a valid configurable address in case of IPv4 and IPv6 point to point networks?

Am I correct, that first address of the subnet is a valid addresses to configure in hosts/routers in case of IPv4 and IPv6 point to point networks? For example, in case of 192.0.2.0/31 one of the ...
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Will hosts do IP Fragmentation?

I heard routers alone do fragmentation. When a host is connected to the network with ethernet cable, how does it keep the MTU size as 1500? Will the host itself fragment and send only 1500 byte ...
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MLD messages during IPv6 duplicate address detection

I was wondering if anyone can shed some light on when Multicast Listener Discovery (MLD) messages ought to be send during IPv6 Duplicate Address Detection. RFC4862 section 5.4.2 gives a detailed ...
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Mitigating a IPv6 malformed packet multicast flood

So we just had our first IPv6 multicast flood in the network this morning. We managed to stop the offending computer by blocking the mac address with: mac-address-table static x.x.x vlan x drop ...
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Why is an IPv6 Link-Local Address a /10?

I'm currently studying for my CompTIA Network+ Exam and am a bit confused as to why the IPv6 link-local address is a /10 and not a /12 or /16. Since each character in an IPv6 address is 4-bits and ...
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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 ...
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Can we do redistribution of ipv4 routes onto v6 address families?

Iam just curious to know whether ipv4 routes can be redistributed to ipv6 address-families. Eg: I have a router for BGP configuration with ipv6 address-family and OSPF in ipv4 with other neighbor. Can ...
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How is NAT a hack?

Forgive me if this sounds a little amateurish, or if this is the wrong stackexchange, but...most of my entirely life I've had ipv4 behind a NAT router. I've been told that this was a hack; simply ...
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OSI layer of Neighbor Discovery Protocol

NDP operates using ICMPv6 and, even though ICMPv6 messages are encapsulated in payload field of IPv6 datagram, ICMPv6 and ICMP are usually considered as network layer protocols. At least, on Wikipedia ...
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Is it possible to run an IPv6 only MPLS core?

I am looking for information on whether it is actually possible to run an IPv6 only MPLS Core with respect to the transport labels, without the current requirement to tunnel across IPv4. To put this ...
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What MAC address do I use to generate a IPv6 Pseudo-Random Global ID

I am setting up a virtual lab environment in the cloud to experiment with IPv6 networks. Bear with me please, I'm new to networking and my grasp of the whole IPv6 subject is quite shaky. Please ...
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DHCPv6 (with PD) client on Juniper SRX

OK, this one may technically be off-topic since I'm actually doing this at home, but I could easily see the exact same scenario arises in a small enterprise type of setup... Using an SRX210 to be a ...
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Stateful vs Stateless IPv6?

What's the difference here? Are stateful IPv6 entries retained in the DHCPv6 server?
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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 <------...
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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 ...
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IPv6 Multicast - Purposes for the Interface-Local scope?

On an IPv6 multicast packet, the last nibble of the first hextet represents the Scope of the packet. This defines effectively how far you want your multicast packet to travel. The address makeup is ...
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Method for assigning IPv6 ULA addresses to LAN

I'm finally embarking on the voyage that is IPv6. I am not sure however, on the best way of assigning a unique local address (ULA) to each host in my LAN. For IPv4 I prefer to have a DHCP server ...
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Wake on LAN across VLANs in IPv6 network

In IPv4, if I want to send a magic packet to a workstation in another VLAN, I enable directed broadcasts in the remote VLAN and send it to the VLAN's broadcast address. This works great. In IPv6, I ...
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IPv6 replacement for ICMP timestamp

Does any standard IPv6 protocol has anything analogous to an ICMP timestamp message?
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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)...
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How to break apart an IPv6 /56 6rd delegated prefix from ISP into multiple /64 VLANs for use with SLAAC EUI-64? [Cisco]

I have CenturyLink Internet service, and they have a 6RD IPv6 deployment where they hand out an IPv6 delegated prefix /56 block to me and allow me to use it as I wish. My Cisco ISR router receives the ...
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Can someone prove me why DHCPv6 needs DAD?

So recently I discovered DHCPv6 needed Duplicate Address Detection but why is that? I had a hard time researching on this topic, most answers is that because it needs first to check but I can't see ...
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777 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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IPv6 unique-local addresses suitable for internal networks

Let's consider a webfarm where each server has two interfaces: one bound to an internal-only, physically separated, network and the other cabled to the switch with the uplink to the public Internet. ...
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497 views

How does router advertisement in IPv6 avoid IP conflict?

If a router advertisement sends the range of subnet, and the client can choose an IP from it, how is there no conflict with another client that has chosen the same address?
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IPv6 and online privacy and security

I am studying up on IPv6 and part of the talk was about how the machines generate or can have multiple IPv6 addresses for internal use and external use. Does this mean that there is no longer a "...
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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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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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Locating a single IPv6 or IPv4 routable prefix at multiple data centers

Academic question (at the moment): Is it possible to advertise BGP routes to a given prefix (IPv6 and/or IPv4) from multiple different physical data centers? I guess this is multi-homing, but ...
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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
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Cisco 6rd configuration example - ipv6 general-prefix

I'm currently learning the IPv6 tunneling via IPv4 in GNS3. I've done manual tunnels, 6to4 and now I'm tackling 6rd. I've read on the subject and I think I get the whole concept..The IPv6 prefix, the ...
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Network Address Translation

The below given diagram is a Static NAT implementation. To ping from an IPv4 client to an IPv6 client across the router we have to ping the IPv4-mapped address of the corresponding IPv6 client. For ...
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Is Path MTU Discovery(PMTUD) really efficient?

As i know, PMTUD uses ICMPv6 to find minimum MTU value in the network path. I understood why IPv6 doesn't allow fragmentation (by reading this article), but PMTUD doesn't look like good manner. here ...
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1answer
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What is the use of the IPv6 scope ID?

In the structure struct sockaddr_in6, the field sin6_scope_id is declared. What is the use of this member? How can we know from the IPv6 address and the prefix length the scope that it should use?
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In networking, is there a word for the first n bytes of an IP address?

I have two IP addresses. They share an IP address to the nth byte. Is there a word that effectively says that they have the same IP address up to the nth byte? Are there different words depending on ...
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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'...
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1answer
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Disadvantages or risks of leaving the the family inet6 configuration under interface configuration in Junos applied

I have a corner-case where I need to leave the family inet6 configuration under IFL present while hosts in that network should not use IPv6. This means, that the logical interface of a router will ...
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address-family ipv6 on Cisco 3560G

Is anyone aware of an IOS version for the C3560G that supports configuring a neighbor to exchange IPv6 routes? Apparently 12.2(37)SE Advanced IP Services can't do it - as soon as you try to activate ...
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How to understand the IPv6 route table [closed]

Here is the ip -6 route result of my working OpenWRT system. I find that this is quite different to the route table of ipv4. default from :: via fe80::3e8a:b0ff:fe86:f870 dev eth0.2 proto ...
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Will a default-deny rule on incoming connections of an IPv6 firewall negate any advantages that were gained by not having NAT?

Will a default-deny rule on incoming connections of an IPv6 firewall negate any advantages that were gained by not having NAT? In other words, one of the most talked about advantages to IPv6 is that ...
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Is it possible to force DHCPv6 to configure address of a client without DHCP Server?

I'm trying to formulate a way to send Ipv6 address to users in my network I'm doing a project where I need to mitigate an attack: The scenario is a user is using SLAAC to genarate its adress but the ...
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Strange IPv6 packet seen when enabling interface on Juniper MX

I have two MX80 routers which are connected. When I enable the interface on one router I get the following packet from the other router which I can't explain: 17:23:46.004429 In IP6 (hlim 1, next-...
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Why there are no different classes of network in IPv6?

In IPv4 we have class A, class B, and class C. In IPv6 we have only global prefix and Interface ID. I know there are plenty of addresses in IPv6 but it gives room for too many host addresses.And when ...
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873 views

Why are IPv6 addresses so long?

By convention, each device on the LAN under IPv6 gets a /64 subnet, right? That's an obscene number of addresses per device! Why not make the addresses shorter, say, 72 bits, then each device would ...
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What does a switch do when the destination MAC address is unknown?

Say I just connected my computer to the internet through a home/office LAN network. I then proceed to ping google.com. Of course, the DNS converts google.com to the destination IP address, but how is ...
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NEWBIE: How can two computers communicate if they are behind firewalls?

This is something I have wondered for awhile and couldn't find answer of. Apologies for the stupid question, but here it goes: If two computers have static IP's then they can easily send each other ...