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215 lines
9.1 KiB
Markdown
215 lines
9.1 KiB
Markdown
---
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layout: post
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comments: true
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title: "IPv6"
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category: [english]
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tags: [english, IPv6]
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redirect_from:
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- /ipv6/
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- /IPv6/
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- /english/2015/06/22/ipv6.html
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lang: en
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robots: noai
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---
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_There appears to be a lot of confusion on IPv6 and in this post I try to clear
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it a little._
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I am writing this post, because
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[TorrentFreak wrote about buggy µTorrent and suggests disabling IPv6 because of it.](https://torrentfreak.com/popular-torrents-being-sabotaged-by-ipv6-peer-flood-150619/)
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The comments of that post are also totally lost.
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<!-- editorconfig-checker-disable -->
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<!-- prettier-ignore-start -->
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<!-- START doctoc generated TOC please keep comment here to allow auto update -->
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<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
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<em lang="fi">Automaattinen sisällysluettelo</em> / <em lang="en">Automatically generated Table of Contents</em>
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- [IPv4](#ipv4)
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- [IPv6](#ipv6)
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- [EUI-64-addresses](#eui-64-addresses)
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- [Windows IPv6 address randomization](#windows-ipv6-address-randomization)
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- [Disabling privacy extensions](#disabling-privacy-extensions)
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- [Getting IPv6](#getting-ipv6)
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- [Further reading](#further-reading)
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<!-- END doctoc generated TOC please keep comment here to allow auto update -->
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<!-- prettier-ignore-end -->
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<!-- editorconfig-checker-enable -->
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## IPv4
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It's probably best to start with what is wrong with IPv4 and note that all
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modern operating systems (including Windows Vista and newer) are designed to
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work with IPv6 and disabling it may break some features.
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There are no IPv4 addresses for everyone and that is why we have NATs in routers
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so we only have one IPv4 address facing the internet. That isn't enough either
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so ISPs started having their own NATs too known as CGN (Carrier Grade NAT)
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putting _a lot_ of customers behind single IPv4 address.
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This means that if someone on the same ISP abused your favourite service X\*,
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all users behind that IPv4 address get banned.
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<em>\*X = Wikipedia, your favourite forum or IRC network or whatever</em>.
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CGN can also cause issues with online gaming (as everyone appears to be
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connecting from single address and it can also increase latencies).
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## IPv6
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IPv6, again, is next version of the Internet Protocol and has enough addresses
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for all your devices and you don't need NAT anymore so you don't have to do port
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forwards (which didn't help you behind CGN anyway) anymore.
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People have weird worries with it and many misunderstandings on privacy
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concerns.
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### EUI-64-addresses
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EUI-64-addresses are based on your MAC-address and a lot of people seem to be
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worried about how they can be used for spying on you as you go through different
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networks (phone, laptop).
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This is an unrequired concern though as IPv6 privacy extensions should exist
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with all IPv6 capable systems (again including Windows which seems to be what
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people worry about the most). The privacy extensions generate a random IPv6
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address which has no MAC-address and is changed over time.
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Arch Linux and Ubuntu MATE (and other Linux distributions?) seem to change it
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every 24 hours (controlled by `net.ipv6.conf.default.temp_prefered_lft`) and I
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believe it also gets changed by reconnecting to network or rebooting the system.
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On your IPv6-enabled system you should see three addresses:
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- EUI-64-address where you see your MAC-address clearly, it just exists and
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isn't used in outgoing connections so no one knows it unless you decide to
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tell them.
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- Privacy (extensions) address which is random and used for all outgoing
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connections and it changes every few hours. You might see multiple of these as
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the old privacy addresses are still kept for some time, but no outgoing
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connections is made with them.
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- Link-local address you see even without global IPv6 connectivity as every
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IPv6-supporting system generates them automatically. They start with `fe80`
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and only work in your LAN. It also has your MAC-address visible.
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If you are still worried about the MAC-address being visible, you can easily
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confirm that no one sees it by going to [ipv6-test.com](https://ipv6-test.com),
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looking at "IPv6 connectivity" and check the test that says "SLAAC". If it says
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"No" your EUI-64-address is not used, if it says "Yes" they are used and it
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should never say "Yes". You will probably understand that it's not supposed to
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say "Yes" as getting "Yes" in that test decreases your score.
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#### Windows IPv6 address randomization
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Windows which you shouldn't worry about makes you worry even less by being
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annoying and randomizing all addresses (even if there is no need because you
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have IPv6 privacy extensions) and this probably causes you a headache if you are
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running Windows Server or dual-booting with some other OS.
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When you dual-boot, you might wonder why even the EUI-64-address is different on
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Windows and Linux/OS X/whatever.
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This is easy to fix though, open cmd.exe or PowerShell as admin and run:
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```
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netsh interface ipv6 set global randomizeidentifiers=disabled store=active
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netsh interface ipv6 set global randomizeidentifiers=disabled store=persistent
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```
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##### Disabling privacy extensions
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**YOU DON'T WANT TO DO THIS UNLESS YOUR PC IS A SERVER AND WON'T EVER BE MOVED
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ANYWHERE. BY DOING THIS THE EUI-64-ADDRESS GETS USED AND EVERYONE DOES SEE YOUR
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MAC-ADDRESS.**
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As I am talking so much about privacy extensions, I must probably tell that you
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can disable them if you want. I have no idea if that is possible with OS X so I
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don't say anything about it, I only know that it uses them by default.
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Windows: start by disabling the randomization and then
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```
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netsh interface ipv6 set privacy state=disabled store=active
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netsh interface ipv6 set privacy state=disabled store=persistent
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```
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Linux: check NetworkManager connection editor (or config files of whatever you
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use) or use the kernel option directly in `/etc/sysctl.conf` or preferably
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`/etc/sysctl.d/<whatever>.conf`: `net.ipv6.conf.default.use_tempaddr=0`.
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The numbers you can use here are:
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- 0 — IPv6 Privacy Extensions are disabled.
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- 1 — IPv6 Privacy Extensions are enabled, but **EUI-64-address is preferred.**
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- 2 — IPv6 Privacy Extensions are enabled and preferred. This is usually the
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default and what you should use.
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### Getting IPv6
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For native connectivity I only know about Finland (links in the list in
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Finnish)…
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- [IPv6 in Finnish consumer connections](https://ape3000.com/ipv6/)
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- At the time of writing Elisa and DNA which are two of three biggest carriers
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(Sonera is missing) have IPv6 in all mobile connections, DNA has IPv6 also
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in broadband connections and Elisa is working on it and Sonera has 6rd.
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- [Elisa's page on enabling IPv6](https://asiakastuki.elisa.fi/ohje/541)
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- [DNA's page on IPv6](https://www.dna.fi/ipv6)
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- [DNA's instructions for enabling IPv6 on different devices](https://www.dna.fi/ipv6-laitteet)
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- [Sonera's page on IPv6 that is worse than earlier ones](https://www.sonera.fi/etsi+apua+ja+tukea/ohjeet/Soneran-palvelut-IPv6-valmiita?id=c4779f91-dd1c-4e43-b026-b2e6338d0db1)
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…but I can suggest searching the web for `yourISP IPv6` and contacting their
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customer support asking when they are going to enable IPv6.
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For tunneling there are multiple services for tunneling and the best are [SixXS]
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and [Tunnelbroker], but I am going to talk more about Teredo which the protocol
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of last resort for accessing IPv6 sites and Windows comeswith it by default. The
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easiest way to enable it is probably saving the following as `something.reg` and
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running it:
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[sixxs]: https://www.sixxs.net/
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[tunnelbroker]: https://tunnelbroker.net/
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```
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Windows Registry Editor Version 5.00
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[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters]
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"AddrConfigControl"=dword:00000000
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[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\TCPIP\v6Transition]
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"Teredo_DefaultQualified"="Enabled"
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"Teredo_State"="Enterprise Client"
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"Teredo_ServerName"="teredo.trex.fi"
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```
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Short explanation:
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- Enable looking up IPv6 records even with Teredo
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- Enable Teredo…
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- …even if we are in domain
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- use teredo.trex.fi as Teredo server, you might want to use some server that is
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[closer to you](https://en.wikipedia.org/wiki/Teredo_tunneling#Servers).
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Linux: install package `miredo` and edit the server in `/etc/miredo.conf` if
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needed.
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And then check [ipv6-test.com](https://ipv6-test.com) and it should detect your
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Teredo connectivity. Some browsers don't even attempt to use it, at least I
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think Google Chrome did so.
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## Further reading
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- [Wikipedia's page on IPv6](https://en.wikipedia.org/wiki/IPv6)
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- [Wikipedia's page on Teredo](https://en.wikipedia.org/wiki/Teredo_tunneling)
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- [Microsoft Technet: A 5 Second Boot Optimization If You’ve Disabled IPv6 on Windows Client and Server by setting DisabledComponents to 0xFFFFFFFF](https://blogs.technet.com/b/askpfeplat/archive/2014/09/15/a-5-second-boot-optimization-if-you-ve-disabled-ipv6-on-windows-client-and-server-by-setting-disabledcomponents-to-0xffffffff.aspx)
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- TL;DR: depending on how you disabled IPv6 your boot might be 5 seconds less
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and Microsoft discourages disabling it and they don't test working without
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IPv6. Disabling IPv6 breaks e.g. HomeGroup.
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_Special thanks to people of `ircs://irc.libera.chat:6697/#IPv6` for checking
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that I don't write total nonsense here and all the fixes made and also @e-ali
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for checking for spelling mistakes._
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