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
936 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 ...
5
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2answers
220 views

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 ...
1
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1answer
248 views

What is the purpose of “Process name” in RIP for IPv6 on Cisco Routers

I was going through Cisco documentation to configure RIP for IPv6. One of the steps says Enables the specified IPv6 RIP routing process on an interface. But they do not go into detail about this ...
43
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4answers
44k views

Why is fe80::/10 reserved for link local addresses when fe80::/64 is actually used?

I understand that IPv6 reserves the fe80::/10 prefix for link local addresses, and that hosts select an address with a /64 prefix. Why is the reserved space so much larger than what is actually used ...
1
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2answers
1k views

no default-router option in dhcpv6?

I'm learning how to program a Cisco router with dhcpv6 and i saw that they never configure the default gateway address in the dhcpv6 configuration . Then how can the pc know what it's gateway address ...
1
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1answer
114 views

IPv6 VPNs source address selection

Say I have the following IPv6 prefix assigned to me by my ISP : 2a01:1000:1000::/48 with 2a01:1000:1000::1/48 assigned to my VPN server. I set up a VPN with a /64 from that block to assign to my ...
0
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2answers
68 views

Internet Protocol versioning - IPv4 and IPv6 [duplicate]

I know that IPv6 is the successor of IPv4. But I don't understand versioning policy. Why not IPv5? Did IPv1, IPv2, and IPv3 exist?
4
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2answers
382 views

What provision does DS-Lite, as used by ISPs, have to provide IPv4 blocks to CPE?

I run a small ISP for a rural community in England. There are around 350 residential properties and 15 small businesses. Three of these businesses run systems that require two consecutive IPv4 ...
-2
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1answer
4k views

ipv6 number of Host Address

I'm trying to find the number of host addresses of IPv6, I know the correct answer is 18.4 × 1018 I cannot seem to correctly calculate the formula to reach the correct answer, please help me. IPv6 = ...
1
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1answer
349 views

Enabling Multicast Listener Discovery (MLD)

Do standard NICs that support IPv6 have the ability to perform MLD? Essentially I understand MLD, but am struggling to find if it needs to be configured or if it is enabled by default on a host. Just ...
14
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5answers
9k views

Duplicate IP Address - which one wins?

If there's a duplicate IP address, which one "wins"? First, last, flaps, neither?
1
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3answers
125 views

How would I make a client find a server with an unknown IPv6 Address?

Let me first explain my situation: I am currently in the process of trying to build a solution for managing multiple Internet of Things devices on a network. It should be possible to automatically ...
1
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1answer
57 views

Design thinking of Solicitation node address in IPv6

Recently I study RFC 4291, and the solicitation node address is defined in that spec. I know what and the function of this solicitation node address. But just wondering why does the address design as ...
1
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1answer
782 views

How does address resolution work with multicast, specifically IPv6?

If I want to send an IPv6 UDP multicast message, how does L3 to L2 address resolution occur? I think I understand ARP and how this same idea applies to unicast, but I am struggling to grasp the idea ...
4
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2answers
876 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 ...
4
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1answer
699 views

IPv4 vs IPv6 performance

What are the differences in performance for IPv4 and IPv6? Is there much of a difference in speed? and what are some of the methods that could be used to test this?
1
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1answer
198 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 ...
1
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1answer
475 views

Max hosts of subnet IPv6

When a interface takes an IPv6 address it does the DAD mechanism. A NS will be sent to the multicast address "solicited node multicast group address". If there is another interface in this multicast ...
1
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1answer
139 views

How can IPv6 host know default router's IPv6 address using RA?

I know an IPv6 host will send Router Solicitation (RS) messages, and a router on the link will reply Router Advertisement (RA) messages. In the RA message, there is the Source Link-Layer Address and ...
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, ...
5
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2answers
2k views

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 "...
1
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1answer
269 views

VRRP VRID configuration for IPv6

Can we use same VRID (VRRP instance) for both IPv4 and IPv6 virtual router in VRRP or VRRP-E? In a layer-3 router, we have requirement to configure interface VE with both IPv4 and IPv6 gateways with ...
3
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1answer
406 views

Finding Subnet Ranges of IPv6

I need to find a single subnet range to cover 10,000 IP addresses (hosts), given the IPv6 Address 2405:1300:c5c1:322::/108 (for example) I am aware of how to do subnet in IPv4 but cannot grasp the ...
1
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4answers
163 views

IS-IS IPv6 over IPv4

In IS-IS the router knows the interfaces addresses of the other routers. So would it be possible to connect two IPv6 areas over an IPv4 area? A router in area A knows that the destination ipv6 ...
4
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2answers
4k 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 ...
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 ...
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 ...
4
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1answer
719 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 ...
2
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1answer
238 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
64 views

Can we use prefix address as the host address in ipv6?

IPv6 I read somewhere that we can use the first and last ip address as host addresses in ipv6. Is it true?
3
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2answers
181 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 ...
3
votes
1answer
342 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 ...
1
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2answers
108 views

How to block outside initiated traffic in NPTv6?

NPTv6 does prefix translation between one IPv6 address to another. Is there a way to prevent outside initiated traffic to inside (preferably in A10 AX devices)?
0
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3answers
4k views

What is a valid public IP address?

What is a valid public IP address? When I was checking my ID to see if it was blacklisted, it came up with the above Amanda… "Please enter a valid public IP address,", so therefore my questions are: ...
4
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1answer
690 views

IPv6 Link-local addresses

RFC 4291 specifies that IPv6 link-local unicast addresses must have a high-order bit sequence of 1111111010, or fe80::/10. However, the same document specifies that the 54 bits following the first 10 ...
8
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2answers
3k views

What are common sizes to split a /29 - /32 IPv6 subnet?

As an LIR, you are getting a /29 to /32 network allocation by the RIPE, but I am a bit overwhelmed by the size of this subnet, and don't find a starting point to split this into common sizes. What we ...
2
votes
1answer
451 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-...
1
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2answers
368 views

IPv6 in PPP - should be an Interface Identifier negotiated FOR both ends of a link? Clarification of RFC 5072 needed

I am trying to implement IPv6 in an existing VPN PPP software, but having hard time of understanding some of the RFC 5072 sections meaning. Namely, section 4.1. Assumption 1: PPP interfaces do not ...
4
votes
1answer
90 views

OSPF - networks/links don't get advertised

In my Multiarea-OSPF configuration I can ping my neighbor, but nobody which is more than one hop away (for instance ABR2). Also traceroute just shows "1 * * * - 2 * * * - 3 * * *" Can ...
6
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2answers
1k views

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 ...
1
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1answer
188 views

IPv6 ACL in Packet Tracer - why doesn't it work?

I typed in this command: ipv6 access-list NO-SERVER-ACCESS permit ipv6 2001:db8:18::/48 host 2001:db8:18:6600::0010 eq 80 permit ipv6 2001:db8:18::/48 host 2001:db8:18:6600::0010 eq 443 permit ...
1
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2answers
780 views

OSPFv3 - Sample configuration (Dual Stack IPv4 and IPv6) - Cheat Sheet

When configuring OSPFv2 on a router, you type in router ospf 10 router-id 1.1.1.1 network 10.0.0.0 0.0.0.3 area 0 for example. That way the network can be advertised per LSAs. But in OSPFv3 it ...
10
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4answers
1k views

IPv4 shortage is now becoming a reality - what is needed for IPv6 to work?

Today I read that Microsoft has no more IPv4 addresses for its Azure cloud. Earlier this week I read that Latin America is out of IPv4 addresses as well. These are real - not predicted - IPv4 address ...
2
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1answer
649 views

IPv6 Testing Addressing Type Confusions

I'm new in the IPv6 Topic and Yesterday I was performing some testing on Cisco IOS and Cisco Routers of the addressing type in IPv6 with RIPng, i was testing the following: Global Unicast Address ...
3
votes
2answers
455 views

How to solve this IPv6 looping problem?

I have set up a 6in4 tunnel, namely "sit1", but I have discovered that if I traceroute non exist IP within the subnet, it will loop. What should I do to solve this? The routing table:
0
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2answers
287 views

Connect old device to IPv6

Hi I'm not an expert on networks and that's the reason why I'm posting this. My problem is that I have an old device (mediacenter box) that does not supports IPv6 to connect to Internet. Until now, ...
1
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1answer
1k 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 ?...
1
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1answer
58 views

Automatically determining ipv6 prefix size to blacklist? [closed]

When writing blacklist automation for my network, is there a way to automatically determine the prefix size of the other party?
3
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1answer
390 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 ...
0
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2answers
671 views

Do we need different VLANs on IPv6 network? [closed]

With IPv6 there's new train of thought around this technology than IPv4. Since this protocol does away with broadcasts, is creating different VLANs necessary? Some people will argue that you can apply ...