Questions tagged [ipv6]

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

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3answers
399 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 ...
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1answer
121 views

IPv6 RAs on Cisco 4500 switch

In a LAN only network without any routers but only two levels of switchs (4500s for core and 2960s for access) I would like to enable IPv6 autoconfiguration for Windows 7 hosts. Is it possible for ...
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5answers
1k views

IPv6 address assigned to vlan interface of 3750 switch changes

When setting up my 3750 stacks, I enable IPv6 on the Vlan1 interface so that I can manage the stack over IPv6. The stacks are not doing any layer 3 routing. However, it seems that the IPv6 address ...
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3answers
3k views

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 ...
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1answer
297 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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1answer
282 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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1answer
77 views

Are there ways on knowing/predecting how long/many are the delay/attempts of Duplicate Address Detection?

Hi guys need help on my project, I was stuck on this research where I am looking for knowing how long is a usual DAD. I'm looking thru the RFC and what I got is that it has a "Random Delay" but ...
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2answers
280 views

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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4answers
2k 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 ...
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2answers
234 views

IPv6 Subnetting - Block RA on Switches?

I'm currently planning a v6 only small datacenter network. Imagine for now one deployment consisting of 6 racks with 12 servers per rack. Each server has 2 NICs for two physically separate networks (...
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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
55 views

Methods on getting the client details on the switch

I have been working on this project and I have come to a point where I need to block the user in the network(At most in the CISCO switch) I know I can send port shut via telnet session with a ...
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3answers
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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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6answers
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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 ...
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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 ...
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3answers
842 views

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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2answers
1k views

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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2answers
802 views

ipv6 Aggregatable global unicast addresses

Studying IPv6 addressing I haven't understood IPv6 aggregable global unicast addresses, I mean on RFC 4291 there is a generic scheme: | n bits | m bits | 128-n-m bits ...
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2answers
433 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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4answers
11k views

What is the proper term for ipaddress/hostname:port

What is the proper term for (example) hostname.tld:433 (hostname:portnumber)? It is not just hostname, and it is not really a URL either :) same goes for 10.0.0.1:3306 etc.
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4answers
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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 ...
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1answer
95 views

How long does an IPv6 neighbour table entry last?

I've been looking around in manuals and Cisco Books, but nowhere have I found how long an entry lives in the IPv6 Neighbour table. If that depends on the implementation, what is it for Cisco?
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3answers
5k views

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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3answers
722 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
1k views

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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2answers
3k views

IPv6 DHCP Server vs Router

I am setting up a testing environment for dualstack. I currently have a server (Windows 2008 R2), 2 switches and a router installed and configured. The server is the Primary Domain Controller and it ...
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4answers
3k views

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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2answers
18k views

IPv6 link-local vs unique local

When do you use link-local or unique local in IPv6 networks? (Cisco doesn't manage to explain it properly in their online material.)
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4answers
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IPv6: Why not use /126 on P2P links for IPv6?

In IPv4 we use /30 to conserve addresses. So why do some people recommend using /64 on P2P links instead of /126? I get using a /64 on regular subnets but isn't using a /64 when there will only ever ...
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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 ...
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2answers
202 views

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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3answers
4k views

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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2answers
2k views

Are IPv6 Wildcard Matches in Cisco IOS Possible?

Facebook is very clever with their IPv6 address scheme, but it got me thinking about ACLs and Is it possible to write a Cisco IOS IPv6 ACL that matches ? In IPv4 you could match a middle octet such as ...
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1answer
731 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 ...
5
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1answer
275 views

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. ...
7
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1answer
216 views

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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1answer
516 views

IPv6 replacement for ICMP timestamp

Does any standard IPv6 protocol has anything analogous to an ICMP timestamp message?
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1answer
8k views

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 ...
6
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1answer
3k views

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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1answer
2k views

Why is IPv6 expressed in hexadecimal format?

Why is ipv6 hex? Is it still okay to express it in denary? sure xxx.xxx.xxx.xxx.xxx is easier to remember than AAAA AAAA AAAA AAAA AAAA AAAA ?
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1answer
636 views

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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1answer
1k views

IPv6: to VRF or not to VRF

Been discussing this with people and reading up, would like people's thoughts on whether or not its worth running IPv6 in a VRF or just let it loose in the global routing table. Even though ...
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3answers
530 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 ...
10
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1answer
487 views

Dynamic Crypto Map with IPv6 access list

I am trying to configure a dynamic crypto map for use on a pure IPv6 network, on Cisco 15.2M. The problem is when I try to add an ipv6 access list to the dynamic crypto map, I get an error message. ...
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3answers
2k views

IPv4 & IPv6 IPSec differences

I am an undergraduate student where I decided to develop a firmware that would eliminate the security vulnerabilities that exist within the current technologies used. such as tunneling, translation ...
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3answers
1k views

How does multihoming work with ipv6?

What are the differences between multihoming in IPv4 versus IPv6? Can an enterprise request a provider-independent IPv6 address space from its RIR/LIR which can be advertised to multiple upstream ...
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5answers
10k views

Duplicate IP Address - which one wins?

If there's a duplicate IP address, which one "wins"? First, last, flaps, neither?
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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 ...
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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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2answers
3k views

IPv6 RA SLAAC prefix lifetime

From what I understand, there is no way to change the prefix lifetime once hosts install the prefix. If I shorten the valid/preferred timer for a prefix, it has no effect on hosts already using the ...

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