Questions tagged [ipv6]

For questions about Internet Protocol version 6 (IPv6); as specified in RFC 8200.

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Network flooded with ICMPv6 Multicast Listener Report Packets

I recently noticed that 3 out of 4 Unifi APs kept reaching 100% CPU usage. When I jumped onto the networks and took a Wireshark capture I noticed 1000s of these packets being sent in just a matter of ...
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2answers
1k views

OSPFv3 (newer commands) not working in Cisco Packet Tracer

The command router ospfv3 1 is not working in the Cisco Packet Tracer (Router: 2811). Does it work somehow or are the IOS version just not up-to-date?
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2answers
189 views

Are IP source and destination fields necessary on LAN?

When sending a packet from one computer to another over LAN, you send both an ethernet header and an IP header. The ethernet header has a source and designation MAC address, and the IP header has ...
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1answer
565 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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2answers
121 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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2answers
261 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 ...
3
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1answer
47 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, ...
3
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1answer
266 views

IPv6 Wireshark filter for partial IP address

I would like to create a display filter with the last 4 octets of an IPv6 address. Basically, I have the mac address with me and I want to filter for the IP address xxxx:xxxx:xxxx:xxxx:113:5005:80:...
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1answer
45 views

Why aren't we encrypting data on Network level instead of transport level when using e.g. HTTP [closed]

Why we are bothering to encrypt our data on a transport level, instead of just doing that on a network level with e.g. IPSec and get rid of the need to to that in upper layers. For example instead of ...
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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 ...
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1answer
994 views

How to calculate the Subnet address?

I have an ipv6 address FC00::50, and the subnet mask length is 64. How to calculate an subnet address? I want address FC00::50 in the scope of this calculated subnet address. Here is the description: ...
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2answers
892 views

EX4200 / EX3300 IPv6 Routing Question

we have about 5 Servers and currently only a cheap L2 Switch. We got an /42 IPv6 Network assigned from our provider and want to route this /42 Network into multiple /64 subnets. These can just be ...
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1answer
78 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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1answer
95 views

Quagga router advertisement messages are wrong after an address change

I have a problem with Quagga OSPFv3 implementation. I have a Mininet topology with a host connected to a router. I assigned an IPv6 address to the router interface. And I enabled IPv6 ...
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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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1answer
719 views

NAT64 return translation doesn't work

I'm doing a NAT64 translation on cisco router. The translation from IPv6 to IPv4 work but the return isn't translated neighter in the NAT64 statistics. config: interface GigabitEthernet0/1 nat64 ...
3
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1answer
436 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 ...
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3answers
5k 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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2answers
386 views

If the IPv6 address will be strictly based on EUI-64 logic then is there any real need of Neighbour Discovery Protocol?

I am building my fundamentals on IPv6 and have realised the multicast group is nothing but FF02::1:FFXX:XXXX. Here xxx is nothing but 24-bits of Mac-address (48 bits) with simple 7th bit magic. ...
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2answers
80 views

What Does a Private IPV6 address look Like?

I'm doing a presentation on how the internet works, and I'm wondering if there is even such a thing as a private IPV6 address. If so, what does a private IPV6 address looks like?
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2answers
104 views

How are IPv6 addresses grouped? [closed]

I apologise off the bat if this question is too basic to belong in this group. Perhaps it can be moved elsewhere if that's the case, or I can be directed to another SE site. With IPv4 I have long ...
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1answer
284 views

How many ipv6 prefixes are currently in use?

Is there a good estimate to how many ipv6 prefixes are currently being used?
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3answers
101 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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1answer
404 views

Does IPv6 Prefix Delegation work with SLAAC, without the need of a DHCPv6 server/client?

All the (cisco) documentation I found about this topic always uses a DHCPv6 server or client to configure Prefix Delegation. But I never read that this is a requirement. Can Prefix Delegation be ...
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1answer
108 views

IPv6 address scheme for network gear

I'm looking for best practice advice on how to IPv6 address your internal infrastructure network gear (routers, switches, etc). In my searching I've seen some people suggest using /127 like in a /30 ...
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2answers
245 views

How does/did an ISP serve so many people over IPv4

Whilst reading Tanenbaum - Computer Networks they talk about IP scarcity at the level of ISPs: IP addresses are scarce. An ISP might have a /16 address, giving it 65,534 usable host numbers. If it ...
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4answers
97 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
66 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, ...
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3answers
10k views

Access Server ipv6 from a ipv4 only network

One of my Server is sitting behind a network which is only accessible trough a IPV6 (no double stack IPv4/IPV6 available). How can I access the server (SSH, HTTP, other protocols) from an network ...
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2answers
990 views

Man In The Middle on IPv6, are IPv4 packets affected?

If I successfully Man in the Middle attack an IPv6 Address of my victim can I also sniff its IPv4 packets? Attacks like Neighbor Advertisement Spoofing or Last Hop Router?
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1answer
62 views

Where is the block which caused IPV4 client can not access IPV6 Server

I read many documents which are saying if you are in IPV4 network then you can not access IPV6 network, for example when I was at home I can not access some IPV6 website, such as:ipv6test.google.com. ...
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1answer
82 views

IPV6 ping, the pinged address is different from the once caught by wireshark

I'm trying to ping an ECU, both PC and ECU have static IPV6 address the problem is that the target address (ECU) pinged is different from the one caught by Wireshark subnet : 64 ping command $ ...
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1answer
76 views

Multhoming including incoming connections?

I am investingating the option of connecting our business network to 2 separate ISPs for redundancy. Since we have a couple of B2B services which need to be accessible from outside, in order to have ...
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1answer
2k views

Why the FF:FE in EUI-64?

EUI-64 IPv6 addresses are generated from MAC addresses by taking the network prefix (64 bits) and appending the first half of the MAC address, then FF:FE, then the second half of the MAC. Is there a ...
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2answers
4k views

IPSec in IPv4 and IPv6

I'm getting a little confused in understanding the differences in IPSec in IPv4 and IPv6... Are the principles of IPsec the same in v6, but instead of it being optional it is now mandatory for it to ...
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2answers
158 views

IPv6 link-local only core network

When planning an IPv6 strategy is it possible to have link-local only addresses within the core transit network (sort of analogous to a BGP-free MPLS core)? If not why not? If yes are there any ...
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2answers
141 views

DAD and link local address

I'm a new guy in IPV6, and now I encounter a question, when ipv6 policy is Auto configuration, is it necessary to DAD on Link local address? my question is, since link local address is created from ...
2
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1answer
102 views

How does IPv6 AH guarranties authentication?

IPv6 Authentication Header uses MD5 hash on the payload, the header, and unchanging fields of the IPv6 header and options to prevent sequence quessing attacks. But all these required information to ...
2
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1answer
337 views

IPv6 VPN addressing

I got two servers with public IPv4 and (now) IPv6 addresses. They have a VPN to do stuff like MySQL replication. With IPv4 I just took a RFC1918 range (10.0.0.0/8) and if you access the server via ...
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3answers
740 views

What is IP address management ? Why its needed ? How does the vendors like Bluecat Networks and Infoblox solves the IPAM problem? [closed]

Recently I heard a term IPAM i.e IP Address management. Theoretically I got the definition from Wikipedia, but couldn't understand its actual need. Since for that we have DHCP then What is the need ...
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1answer
63 views

How can MLDv2 work according to the RFCs 3810 and 4606?

When IPv6 Stateless Address Autoconfiguration is happening, an interface/node has to join the all-nodes multicast address and the solicited-node multicast address AFTER forming a "tentative" ...
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2answers
127 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 ...
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1answer
133 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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1answer
61 views

IPv4 only host on a dual stack environment

I am looking into migrating to IPv6 at my company. Our plan is to dual-stack everything for now, however, we have a couple of local servers that are IPv4 capable only. The rest of our network will be ...
2
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1answer
59 views

Can mobile devices take a global IPv6 address by means of only routing?

I'm probably asking this the wrong way, but here it is; I have a /48 block with static addresses for every device on the network. Everything is routed, no NAT, no tricks. My question is: on a mobile ...
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1answer
277 views

Translation from unique local to global unicast address

is there NAT in IPv6 for private-to-public translation like in IPv4. I know that there is a protocol translation between v4 and v6 but did not find anything about same protocol translation . Thank ...
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1answer
2k views

Is there any difference between Link-local and Site-local scope in IPv6 world?

What is the difference between Node-Local-Scope, Site-Local-Scope and Link-Local-Scope ? What does it mean Link local (link only) ? Is it only for a Subnet ? Why do we need site-local address then ?...
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1answer
661 views

What it means to configure two global ipv6 address on a single interface?

I have seen some network configuration files where a single interface is assigned with two different but similar ipv6 addresses, what is the significance of it, ex : interface te 0/1/0/10 ipv6 ...
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1answer
501 views

MAC Spoofing and EUI-64

I have two questions that both assume an attacker who has my MAC address: Suppose an attacker connects to the Internet before me, spoofing my MAC. I then connect and tell people to connect to my EUI-...
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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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