Questions tagged [ipv6]

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

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2answers
443 views

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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1answer
1k views

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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0answers
829 views

Juniper SRX IPv6-PD update-router-advertisement issues

I'm trying to get some sweet prefix delegation working on my SRX. My provider offers DHCPv6-PD and gives out /56 addresses. I have done setups using cisco routers and am trying to replicate it onto a ...
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4answers
8k views

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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2answers
1k 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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2answers
10k views

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 ...
4
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2answers
5k 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 ...
4
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2answers
133 views

IPv6 addresses allocation

I need to allocate IPv6 /48 block from one provider to another, located in different country. Is it possible at all? I don't own this block but let's assume that current provider will agree to "...
4
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3answers
548 views

IPv6 Multicast vs Unicast

I'm currently learning IPv6 and they mentioned broadcast is gone in IPv6 and replaced with multicast and unicast. Are there some situations where multicast or unicast is better over the other in ...
4
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3answers
166 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 ...
4
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1answer
960 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?
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1answer
159 views

Cisco IOS: OSPFv3 route cost

Cisco IOS 12.4T and later: show ip ospf rib informs about the cost for each network learned by OSPFv2. What command does the equivalent for OSPFv3?
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2answers
748 views

Configure Juniper Router Advertisements

I am currently setting up IPv6 on my network ran by a SRX-240H2 as router. Besides others the router as an internal interface configured as follows: [edit interfaces ge-0/0/4 unit 802] clb@srx01-av# ...
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2answers
6k 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 ...
4
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1answer
1k views

Rogue RA what is this and how to counter it?

This content comes from one of my lectures on "security" module related to IP V6 section. There is no reference in the suggested book or lecture slides what that exactly is. However it is constantly ...
4
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1answer
809 views

Why do some AAAA records behave strangely on existing A records?

I noticed the following odd behavior with AAAA records when querying existing A records. By base domains I mean domain names without subdomains. So when an A record exist and an AAAA record does not ...
4
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3answers
426 views

What is IPv6 trying to fix with Router Advertisements (RA)?

It seems the situation with finding routers in IPv4 with DHCP was okay and now IPv6 has RA's and we have to worry about rogue RA, different vendors provide protection against it, etc. What is IPv6 ...
4
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1answer
553 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 ...
4
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1answer
665 views

Will the packet be dropped when the number of hops equals to default TTL?

From my understanding, the default TTL represents the maximum number of hops allowed such that the packet may reach the host. NTP Documentation Archive: ttl - This option is used only with ...
4
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1answer
533 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 ...
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2answers
441 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 ...
4
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1answer
57 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 ...
4
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1answer
579 views

Network Diagram for IPv6 LAN

From what I understand about IPv6 networks, since NAT was a hack to deal with a lack of IP addresses in IPv4, NAT is a possibility, but not a requirement in an IPv6 LAN. So taking this into account,...
4
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1answer
555 views

TCAM entry width

if IPv4 is 32 bits and IPv6 is 128 bits wide, why TCAM is configured to be 36, 72, or 144 bits wide? why don't configure it as 32, 64, and 128 bits? if there is link for reading material would be ...
4
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1answer
2k views

Cisco & Juniper: IPv6 link-local addresses used between ISIS neighbours

I am configuring IPv6 between a Juniper MX80 and Cisco 7206VXR which already happily run IPv4 over ISIS and iBGP. ISIS is carrying IPv6 routes between the two devices but I have what I believe is a ...
4
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1answer
735 views

Dual stack OSPF redistribution in MP-BGP

My topology is working perfectly fine and is as follows: CE1 <-> PE1 <-> P1 <-> P2 <-> PE2 <-> CE2 CE1 <-> PE1 and CE2 <-> PE2 are having OSPFv3 with ...
4
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1answer
92 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 ...
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2answers
3k views

Host IPv6-only website and allow access to IPv4-only clients

Lets say site.example.com runs only with AAAA records, and I wish to access that site from IPv4-only network, and I don't want to do tunneling neither other protocols that masquerades IPv4 over IPv6 ...
4
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1answer
2k views

MAC address can be used to generate an IPv6 link local address

MAC address can be used to generate an IPv6 link local address. What is the process of using MAC address to derive an IPv6 address ? What are the problems that can be caused due to process of using ...
4
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1answer
743 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 ...
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0answers
55 views

PVLANs/Port isolation in IPv6 networks

We're currently using port isolation to prevent communication between computers on the same vlan and use client isolation on our guest wifi. The reason for having this enabled is to prevent unwanted ...
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0answers
492 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:...
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0answers
423 views

IPv6 link-local addresses for virtual interfaces are identical - how to assign “link-unique”? [closed]

I have a VPN connecting two virtual interfaces of two hosts. Both VPN interfaces have MAC addresses 00:00:00:00:00:00, as the OS (Linux) assigns link-local IPv6 address based on MAC address. So the ...
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2answers
3k 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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4answers
8k views

When it comes to Computer Networks, what is a logical address and physical address?

I understand the concept of logical address, and physical address when it comes to computer memory. That is, physical is the actual address and logical address is what the applications think the ...
3
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3answers
362 views

Which private IP addresses can be used internally?

Does IPv6 have a private IP addressing scheme?
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4answers
3k views

Dual Stack Network Configuration

I am trying to implement Dual Stack configuration of a network in Packet Tracer. I have two routers connected to each other both of these routers have one IPv4 client and one IPv6 client. The routers ...
3
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5answers
268 views

Since we ran out of IPv4 now, what does it mean for consumers?

I'm trying to understand what it means for users... Does it mean that some content will not load on websites, increasingly so in the upcoming year or so? Does it mean that certain CDNs or hostings ...
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3answers
3k views

Is there an renew after the lease-time or after the half of the lease-time in DHCPv6?

Is there an address renew after the lease-time or after the half of the lease-time in DHCPv6 ? I´m not sure about, and I didn´t find that answer inside the RFC of DHCPv6.
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2answers
499 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:
3
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2answers
152 views

Switching to public IPv6

I'm considering the possibility of moving my public addresses to IPv6 for several web applications and sites that I host. When inquiring with my ISP, the account exec replied to me with the following ...
3
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1answer
1k views

What is the advantage of multicasting in IPv6 (compared to broadcast)?

I've been trying to familiarize myself with IPv6 and one thing that's left me hanging is the benefit of multicasting over broadcasting in IPv6. To use Neighbor Discovery Address Resolution as an ...
3
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1answer
98 views

Is it possible to know the mac address or any identification from the user request in DAD?

Is it possible to get an identification like Mac Address in the packet of a DAD attempt that is succesfull? or in the NA Message? I'm trying to narrow down how can I know the client who is replying ...
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2answers
1k views

IPv6 can't ping host when static route configured with exit interface

I have the following topology (using IPv6) interfaces: I have the following static routes configured on it: R1#sh ipv6 route static IPv6 Routing Table - default - 9 entries Codes: C - Connected, L -...
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1answer
438 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 ...
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3answers
4k 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 (...
3
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1answer
388 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 ...
3
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1answer
474 views

IPv6 6to4 mechanism

I'm not sure if I get the idea of 6to4 mechanism. The way I see it: if we have two IP v6 hosts that would like to communicate and all of the internet was IP v6, there would be no problem. However, ...
3
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2answers
234 views

Neighbor Discovery Protocol

When IPv6 is performing NDP and the message is Neighbor Solicitation and the observation point is between two routers, what would the IPv6 source address be? The one from the host or the one from the ...
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1answer
33 views

How to convert size represented in one prefix length to another?

Example, let's say if someone says, I have allocated one /64 address. How can I convert that to a size in /30? How many /30 equals to one /64?

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