IPv6 is the successor to IPv4. Rather than 2^32 addresses (like IPv4), it has 2^128, which is 340,282,366,920,938,463,463,374,607,431,768,211,456 unique addresses (34 undecillion). IPv6 addressing is quite different to IPv4 and is not backwards compatible, but protocols that sit on top (HTTP, SSH, ...

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42
votes
3answers
10k views

How does IPv6 subnetting work and how does it differ from IPv4 subnetting?

This is a Canonical Question about IPv6 Subnetting. Related: How does IPv4 Subnetting Work? I know a lot about IPv4 Subnetting, and as I prepare to (deploy|work on) an IPv6 ...
41
votes
17answers
19k views

Switching to IPv6 implies dropping NAT. Is that a good thing?

This is a Canonical Question about IPv6 and NAT Related: How does IPv6 subnetting work and how does it differ from IPv4 subnetting? How can I 'dip my toes' into dynamic IPv6 ...
33
votes
11answers
8k views

Why would you use IPv6 internally?

Of course, I realize the need to go to IPv6 out on the open Internet since we are running out of addresses, but I really don't understand why there is any need to use it on an internal network. I have ...
32
votes
5answers
2k views

Will everyone having Globally Accessible IP's in IPv6 be kind of a security nightmare? [duplicate]

Possible Duplicate: Switch to IPv6 and get rid of NAT? Are you kidding? I'm thinking about the way that in IPv4 most of the time you have a single point to configure a firewall on, mainly ...
31
votes
1answer
1k views

How can one distinguish the host and the port in an IPv6 URL?

URLs always have this format: <protocol>://<host>[:<port>]/[<path>][#<hash>] The problem is that IPv6 uses colons, just like the separator of port and host, e.g: ...
27
votes
5answers
1k views

Barriers to IPv6 deployment: addressing

There are several things that are keeping IPv6 deployment from being a topic of active discussion here at my work. There are the usual technical issues, but one non-technical one appears to be a major ...
25
votes
5answers
2k views

IPv6 intro for IPv4 admin [closed]

I know IPv4 pretty well, but I've never had to use IPv6 and never really had a class on it or read documentation that made sense. Can anyone point me at a good introduction (on-line or in a book) to ...
25
votes
8answers
40k views

“ipv6 equivalent” of 192.168.x.x (configuring a static ipv6 address)

Background: I have a windows 2008 machine and I want to make it a Domain Controller in a test domain made of two virtual machines. dcpromo pops up a warning if IP addresses for the machine are not ...
24
votes
4answers
3k views

Why can't IPv6 send broadcasts?

IPv4 can broadcast. Why can't IPv6 do that?
24
votes
15answers
2k views

How much is IP V6 addressing being used?

Just how much IP V6 addressing is really in typical use out there? I see that Linux/UNIX seems to be ready for this. But I don't see the readiness as much as the Windows side. Especially not for ...
21
votes
2answers
664 views

Isn't it a huge security issue to include the MAC address inside of an IPv6 address (=default)?

Many times you don't want to be identified while surfing. For one thing your browsing history might be sold without your knowledge, and with no benefit to you.
20
votes
4answers
5k views

Is data always encrypted in IPv6 communications?

I can't seem to get a straight answer to this quesion. Wikipedia says "IPsec is an integral part of the base protocol suite in IPv6," but does that mean that ALL communications are always encrypted, ...
16
votes
2answers
724 views

Convenient public IPv6 test addresses

Are there any convenient public, globally routable test addresses for IPv6? Similar to how 8.8.8.8 and 8.8.4.4 tend to get used this way for IPv4?
16
votes
2answers
827 views

Why is ARIN (etc.) allocating such large blocks of IPv6 addresses?

The whole issue of IPv4 depletion and waste seems to be final getting behind us with the (somewhat) increased deployment of IPv6. The sole purpose of IPv6 was to solve the issue of IPv4 address space ...
16
votes
2answers
595 views

What should a hosting company do to prepare for IPv6?

At the time of writing The IPv4 Depletion Site estimates there are 300 days remaining before all IPv4 addresses have been allocated. I've been following the depletion of IPv4 addresses for some time ...
16
votes
1answer
5k views

nginx name-based virtual hosts on IPv6

I have an nginx server serving up nearly half a dozen different websites. It's running on a Linode that just got IPv6 native support (Dallas data center), and I'm trying to configure most of my sites ...
15
votes
2answers
2k views

What does [::] mean as an ip address? Bracket colon colon bracket

When I run netstat there are some entries such as TCP [::]:8010 computername LISTENING What does that mean? It is impossible to search for...
15
votes
3answers
2k views

Can I bind a (large) block of addresses to an interface?

I know that the ip tool lets you bind multiple addresses to an interface (eg, http://www.linuxplanet.com/linuxplanet/tutorials/6553/1/). Right now, though, I'm trying to build something on top of ...
14
votes
3answers
435 views

What are the IPV6 reserved address spaces?

I'm converting my good old IPV4 based iptables firewall script and would like to substitute the CLASS A/B/C/D/E reserved address spaces to the ones found in IPV6. My goal is to deny any packets that ...
14
votes
3answers
826 views

MySQL Error: (2003, “Can't connect to MySQL server on '2001:db8:81:2c::2' (-9)”)

I'm trying to set up Zenoss 4.2.0 on CentOS 6.3 to monitor a remote MySQL 5.5.25a server via IPv6. The firewall is open for the monitoring server and I can connect fine from the command line: ...
13
votes
5answers
1k views

IPv6: How to start? (ISP perspective)

In our company we have a range of /21 (2048) IPv4 public addresses. We have a bunch of Cisco routers and servers. How to get started with IPv6? What can we do to provide internet to our clients with ...
13
votes
3answers
12k views

How do I add IPv6 address into System32\drivers\etc\hosts?

There is already by default, and it works (Win 7): ::1 localhost This also works (testing with ping): ::1 hosta But when I'm trying to add something non-loopback, it ...
13
votes
2answers
202 views

How can I 'dip my toes' into dynamic IPv6 network addressing?

Is there any way in IPv6 to enable dynamic addressing and configuration for a subset of hosts on a network identified by specific mac addresses? I have been slowly working at setting up IPv6. All my ...
13
votes
3answers
3k views

How do you display the IPv6 NDISC cache in Linux?

Suppose you've configured IPv6 proxy NDP on one of your Linux systems like so: ip -6 neighbor add proxy 2001:db8:1234::5 dev eth1 How do you verify that the configuration took? ip -6 neighbor show ...
12
votes
4answers
580 views

How to prepare (or not) small company to IPv6

There's an ongoing "panic" all over the news for some time now about IPv4 running out and IPv6 being the savior. All the big companies are preparing and showing how it should be done (last actions ...
12
votes
2answers
199 views

How should I temporarily disable IPv6 for an entire network?

We have a medium sized network with IPv4 and IPv6 across it, and our upstream provider is making IPv6 go away for two weeks while they do... something. (It's "experimental" and we don't pay for it, ...
12
votes
2answers
431 views

Why does /proc/net/tcp6 represents ::1 as ::100:0

I was writing an utility to check /proc/net/tcp and tcp6 for active connections as its faster than parsing netstat output. As I dont actually have ipv6 enabled I was mainly utilizing localhost as my ...
12
votes
2answers
1k views

Is there a Linux kernel boot parameter to configure an IPv6 address?

I know there is a parameter named ip which lets you configure IPv4 addresses on the Linux kernel through the boot loader. That looks like the following: ...
11
votes
2answers
425 views

Why is my domain controller causing my router to send advertisements for Unique Local Addresses?

I'm currently evaluating Server 2012 to serve as a domain controller in a small heterogeneous network of Linux and Windows workstations and servers, all of which would eventually be joined to the ...
11
votes
5answers
524 views

How are IP-based rules (eg, bans/filters) affected once IPv6 becomes the standard?

Given that Stack Exchange sites ban on IP, I wonder if there's a common opinion or strategy about making rules based on a user's IP in order to dictate behaviors. With IPv4, you've got a few things ...
11
votes
3answers
783 views

Use Windows DHCP/DHCPv6 server without setting a static address

You cannot set the Windows DHCP/DHCPv6 server to listen on dynamic addresses or all addresses, only static addresses. Is there a technical reason for this limitation? Is there any workaround? My ...
10
votes
2answers
4k views

Should I use IPv6 only or both IPv4 and IPv6 in my web server?

My web server (Ubuntu, Nginx) have both IPv4 and IPv6 addresses assigned by the host. For my website, shall I bind it to only an IPv6 address? Is it the standard recommended way? Or, shall I use both ...
10
votes
7answers
6k views

What are some good, IP Address Management solutions for IPv6? [closed]

There are a number of open source IPAM tools available for IPv4 address management; however there seems to be a distinct lack of actively updated tools available for IPv6. Other than FreeIPdb (code ...
10
votes
3answers
5k views

What is the IPv6 equivalent to IPv4 RFC1918 addresses?

Having a hard time wrapping my head around IPv6 here. A lot of the lingo seems targeted at enterprise-level IPv6 deployments, discussing link-local, site-local, global unicast, scopes, etc. Not a ...
9
votes
5answers
4k views

How can I make my web server reachable via IPv6 on the AWS platform?

My business's web site uses the AWS platform. I want the site's visitors to be able to reach my content using the IPv6 protocol. How can I add an IPv6 address?
9
votes
3answers
2k views

How to prevent delays associated with IPv6 AAAA records?

Our Windows servers are registering IPv6 AAAA records with our Windows DNS servers. However, we don't have IPv6 routing enabled on our network, so this frequently causes stall behaviours. Microsoft ...
9
votes
1answer
633 views

How do I disable IPv4-mapped IPv6?

On my Linux box, I have various daemons which can bind to all IPv6-enabled interfaces on ::. When they do so, Linux sends IPv4 requests to that daemon mapped as, for instance, ::ffff:198.51.100.37. I ...
9
votes
2answers
6k views

Do I need seperate iptables rule for ipv6 address?

On my debian 5.0 server, I setup some iptables rules like below: ACCEPT tcp -- eee.fff.ggg.hhh aaa.bbb.ccc.ddd tcp dpt:80 DROP tcp -- 0.0.0.0/0 aaa.bbb.ccc.ddd ...
8
votes
3answers
2k views

What determines whether the FQDN is interpreted as IPv6 or IPv4?

When I type a Fully Qualified Domain Name (FQDN) in my URL bar, the browser connects to some mapping table (where is this table stored? with the service provider?) that determines where the file ...
8
votes
5answers
3k views

Managing parallel rules for ipv4 and ipv6 iptables?

We've recently started experimenting with IPv6, and one of the first issues we're having to contend with is dealing with a completely separate set of firewall (Linux iptables/ip6ables) rules for the ...
8
votes
2answers
2k views

How do I update my /etc/network/interfaces file so the box comes up with ONLY IPv6 self-assigned address?

I apologize for this blatantly newbie-ish question, but I'd like to do this "the right way" and not just muck about until it seems to work, and the documentation I have doesn't seem to address this ...
8
votes
2answers
308 views

For an internal cluster, is it good idea to use IPv6?

For an internal cluster (db server, web servers etc..), is it good idea to use IPv6, which is faster and more secure? And make use of IPv4 just for the internet connection. Is it good idea? (sorry ...
8
votes
2answers
6k views

IPv6 DHCP Configuration

I want to set up an IPv6 only network for testing. However, I can't find any HOWTOs or information on setting up DHCP to autoconfigure IPv6 DNS server addresses etc. I use radvd on a ubuntu server to ...
7
votes
4answers
3k views

Advantages of IPv4 over IPv6

In theory, how IPv4 is better than IPv6? I need only advantages of IPv4 for study purposes. In another words - what are the pros of IPv4?
7
votes
2answers
680 views

How do I use rsync with an IPv6 address via SSH?

I've been having difficulty with connecting to my IPv6 address via rsync. Because the argument for the destination folder is colon-separated, the IPv6 address disrupts this like so: ...
7
votes
3answers
395 views

What are the downsides of enabling IPv6 in public-facing services?

Our internal network and internal services are IPv6-enabled, and we're considering enabling IPv6 on public-facing SMTP, DNS and Web servers. All the guides / whitepapers I've read on the subject speak ...
7
votes
2answers
701 views

IPv6 without nat but what about an isp change?

I haven't worked with IPv6 outside of 4to6 tunneling on my home pc with stuff like GoGoNet. I've read about how it works in a general way. No NAT required (or suggested) and each client uses a public ...
7
votes
1answer
3k views

TCP/IPv6 thru ssh tunnel

i am wondering how to tunnel tcp/ipv6 traffic over the ssh/ipv4 tunnel (ptp connection). Is it possible? How can i achieve that?
7
votes
3answers
321 views

Should a web server care about IPv6 compatibility?

Are there any IPv6 clients in the real world? If not, is there any other reason to support IPv6? (My understanding is that with the advent of WANs and such IPv6 is not necessary, hence extremely low ...
7
votes
2answers
335 views

IPv6 / IPv4 Third Form conversion?

I'm reading about how to configure IPv6 on Ubuntu, I've gotten to the section about Reading IPv6 Addresses and though the first two examples make sense to me, the last one escapes my grasp a bit, as ...