Questions tagged [ipv6]

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

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1answer
319 views

Why command “ipv6 dhcp relay” doesn't work at packet tracer?

I'm trying to enable dhcp for ipv6 with the "ipv6 dhcp relay dest" command but, I'm receiving an error and I'm trying both of these commands but none work. Router model: 2811 (config)# interface [...
3
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2answers
870 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?
6
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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
286 views

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 ...
1
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1answer
336 views

IPv4 to IPv6 one-to-one mapping for a whole Class A range

Are there any IPv6 technologies that support translating one-to-one mapping from IPv4 to IPv6 for the whole Class A range, like 10.0.0.0/8 network to a particular IPv6/40 range? Preferably for A10 AX ...
2
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1answer
406 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 ...
60
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7answers
17k views

Why are IPv4 addresses running out?

I understand that we are running out (or ran out already?) of IPv4 addresses, but I don't really understand why that is. Right now, every home has its own IPv4 address (dynamically assigned, but still,...
5
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1answer
6k views

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?
10
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4answers
2k views

Using IP subnet at multiple datacenters

We control IPv4 and IPv6 subnets. Now we'd like to use a part of a /24 IPv4 subnet at one datacenter and another part at another datacenter. I know that announcing the subnet on the internet at ...
14
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6answers
23k views

How are IP addresses mapped to MAC addresses?

I've been reading about the differences between MAC and IP addresses, and why we need both of them. To summarize, MAC addresses are physical unchangeable unique IDs for every single device while IP ...
3
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1answer
669 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 ...
4
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3answers
122 views

Native IPv6 load balancing

We have two software gateways (on Linux) for IPv6 that take fullviews from ISPs and announce our AS. And several nodes connected to Internet via the gateways. Something like at picture: And we ...
3
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1answer
75 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 ...
9
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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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0answers
368 views

HSRP IPv6 configuration

Looking at the Cisco documentation for HSRP IPv6 configuration I noticed the use of 'standby 1 ipv6 autoconfig'. interface FastEthernet0/0 no ip address duplex auto speed auto ipv6 address 2020:...
1
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1answer
87 views

IPv6 source address selection: can the source address have a smaller scope than the destination address?

In RFC 6724 section 5 on "Source Address Selection" rule 2 says to "Prefer appropriate scope": If Scope(SA) < Scope(SB): If Scope(SA) < Scope(D), then prefer SB and otherwise prefer SA. ...
0
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1answer
70 views

Why are there IP collisions in my network? [closed]

So I have a switch connected to ethernet cable which has a static IP address configured on it for IPv4 / v6. there are 3 IPv4 static addresses on its subnet. I have 2 Anritsu callboxes connected to ...
2
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1answer
305 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 ...
1
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0answers
55 views

Using IPv6 6in4 tunnel with multiple VLANs, or LAN Interfaces?

I have a pfSense router, and I've setup a Hurricane 6in4 IPv6 tunnel by following this guide: http://thirdinternet.com/wp-content/uploads/2017/11/Configure-6in4-Tunnel-in-pfSense.pdf It all seems to ...
9
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1answer
978 views

What is the use-case of including the IPv4 address in IPv6 address?

It is possible to include the IPv4 address into IPv6 address. For example, 2001:db8::c0a8:6301 where last 32 bits are IPv4 address 192.168.99.1. There is even a special notation of IPv6 address where ...
3
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2answers
4k views

How does computer in IPv4 network communicate with computer in IPv6 network

I have a Verizon cell modem that uses IPv6 addressing only. I can use it to access IPv4 addresses, like browsing the Internet. However, if I try to ping this IPv6 address on a cell modem from IPv4 ...
1
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1answer
50 views

How can know the subnet mask in IPv6 network?

How the host can know the subnet mask in the IPv6 network, in case the network does not use the default subnet mask which is /64. for example the subnet mask of the network is /88, How can the IPv6 ...
9
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2answers
5k views

Is TCP maximum segment size (MSS) “clamping” compatible with IPv6?

With IPv4, TCP MSS "clamping" (a network device editing the MSS value in a TCP header) can help when path maximum transmission unit discovery is not working. (e.g., when ICMP is being blocked ...
5
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1answer
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?
0
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1answer
114 views

Can't connect between an IPV6 network and an added IPV4 router

I have a very simple topology, where 4 routers use IPV6 and RIP, there aren't problems and all devices have connectivity. The issue is if I add another router this time using IPV4 for clients. I ...
13
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3answers
1k views

Where can I use the IPv6 documentation prefix

We are currently building a networking course with a practical part where students have to configure a small network in a virtual environment. However, we are not sure what ipv6 prefixes we can use ...
1
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2answers
98 views

Is it possible to see a Teredo IPv6 address in IPv6 neighbor cache?

Is it possible to see a Teredo address (from 2001::/32 block) in an IPv6 neighbor cache? For example, in the case of Junos, in the output of show ipv6 neighbors. As much as I tested, this is not ...
1
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1answer
37 views

Is it possible that IPv6 multicast address is shown in the “IPv6 Address” column of the “show ipv6 neighbors” command in Junos?

Is it possible that IPv6 multicast address(i.e address from ff00::/8 address block) is shown in the "IPv6 Address" column of the "show ipv6 neighbors" command in Junos?
1
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2answers
3k 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 ...
91
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12answers
28k views

IPv6 address space layout best practices

I'm comfortable with IPv4 address space allocations. By which I mean: Given services to plan for, or an organization to network, I have a good grasp of how to plan IP address space usage. (or at least,...
10
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1answer
2k views

Does IP provide QoS or not?

IP provides a best-effort delivery service. I believe this implies, among other things, that it offers no QoS to the users. However, IP has a byte in its headers (ToS in v4 and Trafic Class in v6) ...
1
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2answers
2k views

How to check if switch is ipv6 fully compatible

We will move to IPv6 in the next months and I have a lot of switches and routers and I want to discard IPv6 non-compatible or not fully compatible devices. What kind of standar I will need to check ...
1
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3answers
8k 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 ...
0
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1answer
71 views

Trade Floor Network Design Feedback [closed]

I have an assignment that I am working on. Now I admit, I am far from knowledgeable and I have nowhere to turn to for help at the moment. I am not asking for someone to complete the assignment for me, ...
1
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0answers
161 views

How is the source link-layer address in IPv6 router solicitation(RS) messages used?

When I analyze the router solicitation(RS) messages, then they contain the MAC address of the sending host. How does the router use this MAC address seen in ICMPv6 message? Does it simply use it as a ...
1
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2answers
195 views

How does WAN work?

I understand the basics. WAN is a network that connects multiple LANs together. Usually the router is the connection between the LAN and WAN. But I have some questions books and the internet could not ...
5
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2answers
336 views

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 ...
2
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2answers
326 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. ...
1
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1answer
751 views

What are the key advantages and disadvantages of NDP compared to ARP?

So why they didn't use ARP in IPv6? is there any real benefit of doing this? what are the key advantages and disadvantages of using NDP instead of ARP? (In overall network performance, Security and ...
0
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1answer
101 views

Implications of ipv6 on LAN security [duplicate]

I'm not sure whether this is really the correct place to post this question, because it's not really about a "professional" setting. However, I have the standard setup with computers behind a netgear ...
4
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1answer
432 views

IPv6 - ULAs - Am I understanding use correctly?

Tinkering more with IPv6 and trying to unlearn the IPv4 stuff. Assume my router is correctly respecting the reserved addresses. LLIPs aren't going to pass through to the router's outside interface ...
71
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5answers
30k views

Is “IPv10” a joke or a serious RFC draft?

Internet Protocol version 10 (IPv10) Specification The name is funny (IPv4 + IPv6 == IPv10), but the actual proposal looks strange (one more packet format to battle incompatibility between packet ...
7
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1answer
909 views

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 ...
1
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1answer
71 views

ISATAP configuration not working when adding hosts

I am trying to make an ISATAP configuration where two ipv6 hosts connected to dual stacked routers can communicate to each other. I have the following configuration: I have configured RIP across ...
3
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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 (...
6
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0answers
547 views

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 ...
38
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5answers
7k views

Why does ipv6 specify 128 bit address, when there are only 48 bits in MAC addresses?

So, I'm reading for a networking exam, and I'm just wondering if I have missed something basic. Is there a need for more ip addresses than MAC addresses, and how would a node with one network adapter ...
0
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2answers
46 views

When neigbour solicitation and router solicitation are used to get the IPv6 address, then what is the role of 0:0:0:0:0:0:0:0/128?

I am learning computer networks, but getting confused each time I proceed my analysis. Kindly help. Thanks in advance!
-1
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1answer
81 views

Sending image files using GNS3

I had built a network using GNS3, this network contains a lot of routers, the problem is: I want to send an image file between these routers using GNS3 is there any way to do that?
3
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1answer
932 views

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 ...