Différences

Ci-dessous, les différences entre deux révisions de la page.

--- travaux:ipv6-faq [2014/05/01 16:56]
sthibaul [iptables]
+++ travaux:ipv6-faq [2018/06/19 02:20] (Version actuelle)
sthibaul [Why should I enable IPv6?]
@@ Ligne 1: / Ligne 1: @@
 ======= IPv6 FAQ =======
@@ Ligne 5: / Ligne 6: @@
 This FAQ is released under the WTFPL version 2. Please share it as much as possible, correct it (and it would be nice to feed back corrections), translate it, share it again, compress it, share it again.
-This FAQ is meant as a quick-starter for people wondering about adding IPv6 support to their network. It is not meant as a documentation, just as a FAQ, so please keep the contributed answers small and simple. They can however contain links to documentations. Also, sometimes simplifications are made on purpose because on first approach they are OK, so please techies bear with them :)
+This FAQ is meant as a quick-starter for people wondering about adding IPv6 support to their network. It is not meant as a documentation, just as a FAQ, so please keep the contributed answers small and simple. They can however contain links to documentations. Also, sometimes simplifications are made on purpose because as a first approach they are OK, so please techies bear with them :)
 If you are wondering about adding IPv6 support and see one of your questions not answered here, please add the question, and lurkers will add the answer :)
@@ Ligne 24: / Ligne 25: @@
   * Because there are no IPv4 addresses any more.
-  * Because this permits to give a public IP address to all equipments (computer, phone, tablet, video game consoles, recorder, etc.) without having to use NAT any more, because there are a *lot* of IPv6 addresses (almost a million of billions of billions of IPv6 adresses per earth square meter, which is dozens of thousands of IPv6 /64 networks per earth square meter), compared to IPv4 addresses, which are now nowhere to be found.
+  * Because this permits to give a public IP address to all equipments (computer, phone, tablet, video game consoles, recorder, etc.) without having to use NAT any more, because there are a *lot* of IPv6 addresses (almost a million of billions of billions of IPv6 adresses per earth square meter, or dozens of thousands of IPv6 /64 networks per earth square meter), compared to IPv4 addresses, which are now nowhere to be found.
   * Because there are no IPv4 addresses any more.
   * Because you have the opportunity to rethink your addressing scheme.
   * Because there are no IPv4 addresses any more.
-  * Because IPv4 will be yet more and more painful to make working at all.
+  * Because IPv4 will be yet more and more painful to make working at all. We have kept piling up tricks to continue using IPv4, but that has already cost more than just migrating to IPv6, and continue costing **again** even more than just migrating to IPv6.
-  * http://www.youtube.com/watch?v=eYffYT2y-Iw
+  * Because there are no IPv4 addresses any more.
-  * TODO: more
+  * https://labs.ripe.net/Members/david_holder/blockers-to-ipv6-adoption
+  * https://www.ipv6.com/general/top-10-features-that-make-ipv6-greater-than-ipv4/
+  * https://www.youtube.com/watch?v=d8wIdd2fNmk
 TODO: links to details
@@ Ligne 38: / Ligne 42: @@
 ===== Is IPv6 very different from IPv4? =====
-Basically no, the principles of IPv6 are very close to IPv4, even more so since IPv4 has more and more converged toward IPv6, using CIDR, multiple addresses, IPv6 now has NAT, etc. The differences one will have to cope with anyway are:
+Basically no, the principles of IPv6 are very close to IPv4, even more so since IPv4 has more and more converged toward IPv6, using CIDR, multiple addresses, and IPv6 now has NAT, etc. The differences one will have to cope with anyway are:
-  * 128bit addresses instead of 32bit addresses, with an [[https://en.wikipedia.org/wiki/IPv6_address#Presentation|hexadecimal notation]], like 2001:db8:12ab::12 (although it's not mandatory to use a-f letters: one can decide to just use numbers for the right part of the address for instance)
+  * 128bit addresses instead of 32bit addresses, with a [[https://en.wikipedia.org/wiki/IPv6_address#Presentation|hexadecimal notation]], like 2001:db8:12ab::12 (although it's not mandatory to use a-f letters: one can decide to just use numbers for the right part of the address so as to get the same IPv4 and IPv6 addresses visually, for instance)
-  * Prefix sizes are thus between 0 and 128, e.g. 2001:db8::/64
+  * Prefix sizes are thus between 0 and 128, usually one uses /64, e.g. 2001:db8::/64
-  * Well-known addresses are of course different, e.g. 127.0.0.1 is ::1 in IPv6.
+  * Well-known addresses are of course different, e.g. 127.0.0.1/8 is 0::1/128 in IPv6.
-  * Interfaces always have at least an IPv6 address in fe80::/10, which is only used on the link scope (e.g. for NDP, see below). This is actually quite like IPv4's automatic private IP adressing (169.254.0.0/16), now systematic.
+  * Interfaces always have at least an IPv6 address in fe80::/10, which is only used on the link scope (e.g. for NDP, see below). This is actually quite like IPv4's automatic private IP adressing (169.254.0.0/16), but now systematic.
-  * DNS entries for IPv6 use "AAAA" records instead of "A" (but they're basically the same), a domain will thus have both AAAA entries for its IPv6 addresses, and A entries for its IPv4 addresses.
+  * DNS entries for IPv6 use "AAAA" records instead of "A" (but they work the same way), a domain will thus have both AAAA entries for its IPv6 addresses, and A entries for its IPv4 addresses.
   * IPv6 and IPv4 can not natively talk to each other. More on this below.
 ===== Do I have to completely migrate to IPv6? =====
-Well, in the end, all machines should have IPv6 configured. But that does not mean one has to get rid of IPv4 immediately. One can simply add IPv6 along IPv4, and IPv6 will be used whenever it can be, while IPv4 can still be used as a fallback, even if it is behind a CGN.
+Well, in the end, all machines should have IPv6 configured. But that does not mean one has to get rid of IPv4 immediately. One can simply add IPv6 along IPv4, and IPv6 will be used whenever it can be, while IPv4 can still be used as a fallback, even if it is behind a CGN (see about CGN below).
+That said, a combination of NAT64 + DNS64 can be used to set up an IPv6-only network, which can still transparently access the IPv4 world, see more on this below.
-The combination of NAT64 + DNS64 can however be used to set up an IPv6-only network, which can still transparently access the IPv4 world.
 ===== Is IPv6 slower than IPv4? =====
-There is no general answer to this. For various reasons, IPv6 is faster to process than IPv4 (e.g. no checksum in the IP header, no fragmentation, which brings huge savings for routers). For others, it is slower (e.g. bigger addresses, leading to 1.33% bandwidth overhead on typical networks). IPv6 implementations might not have yet gotten as optimized as IPv4 ones. But the routing tables are much cleaner. In the end, some applications simply try both, and use the one that connects first, so whichever it is wins :) IPv6 also makes way less use of ethernet broadcasts.
+There is no general answer to this.
+For various reasons, IPv6 is faster to process than IPv4 (e.g. no checksum in the IP header, no fragmentation, much simpler routing tables, which brings huge savings for routers, and much less use of Ethernet broadcasts).
+For other reasons, it is slower (e.g. bigger addresses, leading to 1.33% bandwidth overhead on typical networks, and implementations might not have yet gotten as optimized as IPv4 ones).
+In the end, some applications simply try both, and use the one that connects first, so whichever it is wins :)
 ===== Does my machine support IPv6? =====
@@ Ligne 74: / Ligne 86: @@
 ===== How does DNS work with IPv6? =====
-DNS replies contain both IPv4 answers (in A records) and IPv6 answers (in AAAA records), independently of the protocol which was used for the request/reply:
+DNS replies contain both IPv4 answers (in A records) and IPv6 answers (in AAAA records), independently of the protocol which was actually used to transport the request and reply themselves:
   $ dig -4 any www.ffdn.org
   ...
-  www.ffdn.org.		86400	IN	A	141.255.128.13
+  www.ffdn.org.		86400	IN	A	185.233.100.13
-  www.ffdn.org.		86400	IN	AAAA	2a01:474::13
+  www.ffdn.org.		86400	IN	AAAA	2a0c:e300::13
   ...
   $ dig -6 any www.ffdn.org
   ...
-  www.ffdn.org.		86400	IN	A	141.255.128.13
+  www.ffdn.org.		86400	IN	A	185.233.100.13
-  www.ffdn.org.		86400	IN	AAAA	2a01:474::13
+  www.ffdn.org.		86400	IN	AAAA	2a0c:e300::13
   ...
@@ Ligne 96: / Ligne 108: @@
   * Configure your host operating system for IPv6 (unless automatically done through dynamic configuration or stateless auto-configuration)
   * Make sure your applications know how to connect through IPv6.
+Those are summarized below.
 ==== How do I enable IPv6 for my server applications? ====
@@ Ligne 104: / Ligne 118: @@
   * Configure your host operating system for IPv6 (unless automatically done through dynamic configuration or stateless auto-configuration)
   * Make sure your server software listens for IPv6 connections
-  * Publish DNS AAAA records, so people start connecting to your server
+  * Publish DNS AAAA records, so people start connecting to your server through IPv6.
+Those are summarized below.
 ==== How to bring IPv6 routing up to my machine? ====
-Hopefully, your ISP brings IPv6 up to your router. You then just need to configure the router to route IPv6 (that step will be extremely similar to IPv4 routing), and for instance configure DHCPv6 or stateless autoconfiguration, as well as Router Advertisement (RA), so you don't need to configure your machine's operating system.
+Hopefully, your ISP brings IPv6 up to your router, if not, ask them for it. You then just need to configure the router to route IPv6 (which is extremely similar to IPv4 routing, with BGP and OSPF (version 3) for instance).
-You also need to make sure IPv6 resolution works. For instance, ''host www.ffdn.org'' should report both 141.255.128.13 and 2a01:474::13. If not, you need to configure your DNS server to enable IPv6 AAAA records.
 If your ISP does not bring IPv6 up to your router, you can use an IPv6 tunnel, see below.
-Of course, don't forget to set up a firewall along the way. Yes, a firewall, not NAT.
+Of course, don't forget to set up a firewall along the way. Yes, a firewall, not NAT, see below.
-[[http://v6.testmyipv6.com/]] can be used for instance to easily test that it worked fine.
 ==== Does my ISP bring IPv6 up to my router? ====
   * France:
     * Renater's core routes IPv6, but a lot of universities and laboratories have not configured their end yet.
-    * Free provides a /60, but as of jan' 2014, it does not provide a firewall feature on the router to protect it.
+    * Free provides a /60 prefix, but as of jan' 2014, it does not provide a firewall feature on the router to protect it.
     * Nerim provides IPv6
     * FDN provides a /48 prefix
     * TODO...
   * TODO...
-==== How to configure my server operating system for IPv6? ====
-The simplest way is simply not to have to configure it, by just configuring DHCPv6 or stateless autoconfiguration on your router. Machines on the network will then automatically configure themselves, just like they can do for IPv4.
+==== How to configure my server or client operating system for IPv6? ====
+The simplest way is simply not to have to configure it, by just configuring DHCPv6 or stateless autoconfiguration, as well as Router Advertisement (RA) on your router, see the "quick examples" section. Machines on the network will then automatically configure themselves, just like they can do for IPv4.
+You can however also configure the IPv6 address, default gateway and DNS server by hand, similarly to manual configuration of the IPv4 address.
+You need to make sure IPv6 resolution works. For instance, ''host www.ffdn.org'' should report both 185.233.100.13 and 2a0c:e300::13. If not, you need to configure your DNS server to enable IPv6 AAAA records (TODO: tell briefly how in the "quick examples" section).
+[[http://v6.testmyipv6.com/]] can be used for instance to easily test that it worked fine.
-You can however also configure the IPv6 address, default gateway and DNS server by hand, similarly to the configuration of the IPv4 address.
 ==== How to make sure my client software knows how to connect through IPv6? ====
-You can tcpdump your network interface, or use netstat, etc. If the application does not seem to support IPv6, please report a bug to their authors. Nowadays, all applications should really support IPv6.
+You can use ''tcpdump -i eth0 ip6'' , or use ''netstat -Ainet6'' , etc. to see how it connects. If the application does not seem to support IPv6, please report a bug to their authors. Nowadays, all applications should really support IPv6.
 One can force the application to use IPv6 by specifying the IPv6 address by hand. This can for instance be done in URLs, by putting the address inside braces (to avoid confusion with the TCP port number), for instance http://[2001:db8::1]/
 A lot of command-line tools (e.g. ssh, wget, dig, ...) have ''-4'' and ''-6'' options to force the use of IPv4 or IPv6.
-==== How to make sure my server software listens for IPv6 connections? ====
-One can see this in netstat -Ainet6, e.g.:
+==== How to make sure my server software listens to IPv6 connections? ====
+One can see this in ''netstat -Ainet6'', e.g.:
 ''tcp6       0      0 :::22                   :::*                    LISTEN      5265/sshd''
@@ Ligne 147: / Ligne 166: @@
 ssh is properly listening on TCPv6 port 22.
-Some software may have to be explicitly told to listen for IPv6, by specifying things like
+Some software may have to be explicitly told to listen to IPv6, by specifying things like
 ''listen = 0.0.0.0, ::''
-where 0.0.0.0 is for all IPv4 addresses, and :: is for all IPv6 addresses.
+where 0.0.0.0 is for all IPv4 addresses, and :: is for all IPv6 addresses. See the "quick examples" section.
 ==== How to publish AAAA DNS records ====
-IPv6 AAAA DNS records are just like IPv4 A records, except they contain an IPv6 (which is 4 times bigger than an IPv4, thus the 4 A's :) )
+IPv6 AAAA DNS records are just like IPv4 A records, except they contain an IPv6 (which is 4 times bigger than an IPv4, thus the 4 A's :) ). For instance, here 'myserver' has bothe an IPv4 and an IPv6:
+''myserver	IN	A	192.0.2.13''
+''myserver	IN	AAAAA	2001:db8::13''
 ===== Can an IPv6-only machine A connect to an IPv4-only machine B? =====
-Not natively: there has to be a router ''R'' in-between which has both IPv6 and IPv4 configured, and performs **NAT64** address translation.
+Not natively: there has to be a router ''R'' in-between which has both IPv6 and IPv4 configured, and performs **NAT64** address translation for instance:
-''A'' will send IPv6 packets using its IPv6 address as source, and will encode the IPv4 address of the destination in the ''64:ff9b::/96'' prefix.  For instance, a destination of ''192.0.2.128'' will become ''64:ff9b::c000:0280'', which can also be written as ''64:ff9b::192.0.2.128'' to clearly show the mapping. ''B'' will send and receive IPv4 packets, using its ''192.0.2.128'' address.  Note that it's also possible to use any ''/96'' prefix inside your assigned IPv6 address space to perform the translation, instead of the well-known prefix ''64:ff9b::/96''.
+''A'' will send IPv6 packets using its IPv6 address as source, and will encode the IPv4 address of the destination in the ''64:ff9b::/96'' prefix; for instance, a destination of ''192.0.2.128'' will become ''64:ff9b::c000:0280'', which can also be written as ''64:ff9b::192.0.2.128'' to clearly show the mapping (it's also possible to use any ''/96'' prefix inside your assigned IPv6 address space to perform the translation, instead of the well-known prefix ''64:ff9b::/96'').
+''B'' will send and receive IPv4 packets, using its ''192.0.2.128'' address.
 All the magic happens at the router in-between: it will translate both ways, masquerading the IPv6 address of ''A'' with its own IPv4 address (**stateful** translation) or dynamically assigning IPv4 addresses as needed to map IPv6 clients (**stateless** translation).
@@ Ligne 167: / Ligne 190: @@
 Since ''A'' should always try to contact ''B'' as ''64:ff9b::c000:0280'', its DNS resolver should provide ''DNS64''.  It works by replacing the ''A'' records in DNS answers with the corresponding ''AAAA'' records in the ''/96'' translation prefix.
-See http://www.kafe-in.net/page/15 (in French)
+See http://www.kafe-in.net/page/15 (in French). TODO: english documentation on this.
 ===== Can an IPv4-only machine A connect to an IPv6-only machine B? =====
-No. A will only be able to connect to B by setting up an IPv6 tunnel on it (i.e. A will not IPv4-only any more actually). See more about it below
+No. A will only be able to connect to B by setting up an IPv6 tunnel (i.e. A will not be IPv4-only any more actually). See more about tunnels below.
 ===== What is an IPv6 tunnel? =====
-It is a tunnel with one end connected to the IPv6 world, thus letting a machine in an IPv4 world have a route to the IPv6 world. A huge lot of various tunnel possibilities exist (TODO: mention a list, but without going into details, just urls).
+It is a tunnel with one end connected to the IPv6 world, thus letting a machine in an IPv4 world have a route to the IPv6 world. A huge lot of various tunnel possibilities exist (TODO: mention a list, but without going into details, just URLs). Ideally you should not use a tunnel, and just convince your ISP to bring IPv6 to you natively.
 ===== I have heard that IPv6 is less secure because it does not have NAT, is that so? =====
-Well, IPv6 does have NAT support nowadays actually (In Linux: starting from kernel 3.7), but using NAT has drawbacks (see below).
+Well, IPv6 does have NAT support nowadays actually (see below), but using NAT has drawbacks (see below).
-And not using NAT does not make your network less secure. What can make your network less secure is not using a firewall at all. It happens that enabling NAT would usually automatically enable a firewall. But you can also enable a firewall, thus getting security, without enabling NAT (which does not bring security but breaks things).
+And anyway, using NAT does not make your network more secure. What can make your network less secure is not using a firewall at all. It happens that enabling NAT would usually automatically enable a firewall. But you can also enable a firewall, thus getting security, without having to enable NAT (which does not bring security but breaks things).
 ===== Is NAT available with IPv6? =====
-With recent versions of Operating Systems, yes (TODO: which versions).
+With recent versions of Operating Systems, yes (In Linux: starting from kernel 3.7).
 That being said, this is usually not a good idea, as NAT breaks a lot of application protocols, see below, and IPv6 is precisely meant to let all machines have their own public IP.
-If you really really want to, you can use a random fd00::/8 prefix for defining a private local network.
+If you really want to, you can use a random fd00::/8 prefix for defining a private local network, see below.
 ===== What are the downsides of NAT? =====
-  * In IPv4, because it only shifts the lack of addresses a bit: instead of lacking addresses, you are then lacking ports on the few public addresses you are using to masquerade the private addresses. This limits the number of connections each machine can keep open at the same time.
+  * In IPv4, it only shifts the lack of addresses a bit: instead of lacking addresses, you are then lacking ports on the few public addresses you are using to masquerade the private addresses. This limits the number of connections each machine can keep open at the same time. This leads for instance to broken images in web pages (because the webbrowser tried to load them in parallel, and that failed).
   * It breaks protocols which explicitly use IP addresses
     * FTP
@@ Ligne 198: / Ligne 222: @@
     * IRC's DCC
     * Voice over IP: SIP
-    * And any such protocol that anybody on earth might want to invent. Firewall plugins might have been written to cope with the protocols above, but they can not work with newer protocols.
+    * And any such protocol that anybody on earth might want to invent. Firewall plugins can be written to cope with the protocols above, but they can not automatically work with newer protocols that people invent.
   * Consequently, it makes protocols try to deal with NATs, which makes them much more complex.
+===== Why CGN has more downsides? =====
+Well, it's basically the same as NAT, but to a larger scale: Carrier-Grade NAT (CGN) means it is all customers of an ISP which are masqueraded behind the same public IP addresses, and out of control from the customers. As a consequence:
   * All users sharing the same public IP address appear the same on the Internet.
     * If one of them gets blacklisted based on its IP address, all of them get blacklisted. This has already happened on a very large scale due to CGN.
-    * Tracing a network issue gets more complex when you only have a public IP address behind which there are thousands of customers.
+    * Tracing a network issue gets more complex when you only have a public IP address behind which there are hundreds of customers.
-    * If a customer does bad (really bad) things on the Internet, the police would like to know who that is, not which pack of thousands of people that might have been at some more or less unknown point.
+    * If a customer does bad (really bad) things on the Internet, the police will want to know who that is, but they will only know which pack of hundreds of people happened to use that IP address at some more or less unknown point.
   * machines behind the NAT require port forwarding to act as servers. This hinders innovation.
+  * ISPs have millions of customers, 10.0.0.0/8 contains only 16 million IPs.
-===== Why CGN poses more downsides? =====
+  * Geolocalisation of customers can not happen any more.
+  * NAT is usually also performed again at the customer's homes. These two layers of NAT make it rather impossible to support peer-to-peer exchanges.
-Well, it's basically the same as NAT, but first to a larger scale: Carrier-Grade NAT (CGN) means it is all customers of an ISP which are masqueraded behind the same public IP addresses. Also, ISPs have millions of customers, 10.0.0.0/8 contains only 16 million IPs. Geolocalisation of customers also can not happen any more.
+  * The CGN not being controlled by the customer, mostly only TCP and UDP will get through (ICMP too, if the ISP is no too dumb). This hinders possibilities of innovation in the transport layer.
-It is also worse because NAT is usually also performed again at the customer's homes. These two layers of NAT make it rather impossible to support peer-to-peer exchanges.
-Last but not least, the NAT not being controlled by the customer, mostly only TCP and UDP will get through (ICMP too, if the ISP is no too dumb). This hinders possibilities of innovation in the transport layer.
 ===== Do I have to rethink my firewall rules? =====
@@ Ligne 218: / Ligne 243: @@
 Essentially, no, since IPv6 uses the same basic principles of IPv4. So the firewall rules will essentially be the same. This is thus duplicated configuration lines, but not duplicating thinking about them.
-One exception to this is:
+Two exceptions to this are:
   * ARP is replaced with NDP, which is contained in ICMPv6, so make sure to enable ICMPv6 (at least types neighbradv and neighbrsol) on prefixes fe80::/64 and ff02:0:0:0:0:1:ff00::/104, so it can work properly.
+  * Routers do not fragment packets any more, so be sure to let ICMPv6 packet-too-big pass, so clients can discover the PMTU (Path MTU) automatically.
 (TODO: any other?)
+See the "quick examples" section.
 ===== Do I have to rethink my addressing scheme? =====
 Well, it can be a good opportunity to clean up the addressing scheme. That said, you don't strictly have to, since there is so much room, you could even, for a machine which has IPv4 192.0.2.128, simply give it the IPv6 2001:db8:0:2::128, thus looking very similar to the IPv4.
+Since there is so much room, one can use prefix sizes that are multiple of 4, and thus not have to care about bitmasks any more since network/host division will then always be between two hexadecimal digits.
 ===== Which addresses can be used for local use? (i.e. equivalent of 192.168.0.0/16 etc) =====
@@ Ligne 232: / Ligne 262: @@
 A very strict equivalent would be using prefixes in fec0::/10 (site-local addresses). For instance, one can typically use fec0::/64.
-One of the issues in IPv4 was however when merging two networks which use 192.168.0.0/16, which leads to addresses conflicts. For the same reason, these site-local addresses are deprecated, because the very notion of "site" can vary, leading to various issues.
+One of the issues in IPv4 is however when merging two networks which already use 192.168.0.0/16, which leads to addresses conflicts. For the same reason, the IPv6 site-local addresses are deprecated, because the very notion of "site" can vary, leading to various issues.
-For this reason, it is recommended to rather use Unique Local Addresses (ULA): take one 40-bit random number for your site, and append it to fd00::/8, leading to a /48 prefix. For instance, one could end up with fd12:3456:789a::/48. Then one can define up to 65536 /64 prefixes in it: fd12:3456:789a:1::/64 for instance. That last step is just like one was defining 10.x.y.0/24 IPv4 prefixes for instance. When two sites merge, since each of them has taken a random number, there is very low probability of collision. The [[https://www.sixxs.net/tools/grh/ula/|SixXS database]] can be used as a registration base. This is voluntary only, but helps reducing risks of conflicts.
+For this reason, it is recommended to rather use Unique Local Addresses (ULA): take one 40-bit random number for your site, and append it to fd00::/8, leading to a /48 prefix. For instance, one could end up with fd12:3456:789a::/48. Then one can define up to 65536 /64 prefixes in it: fd12:3456:789a:1::/64 for instance. That last step is just like when one is defining 10.x.y.0/24 IPv4 prefixes for instance. When two sites merge, since each of them has taken a random number, there is a very low probability of collision. The [[https://www.sixxs.net/tools/grh/ula/|SixXS database]] can be used as a registration base. This is voluntary only, but helps reducing any risks of conflicts.
 ===== How does dynamic routing work? (BGP,OSPF,...) =====
-Essentially the same way as IPv4 dynamic routing, simply alongside IPv4, for instance by running a bgp daemon for IPv4, and another one for IPv6. You can for instance have exactly the same peering policy (at least with your peers who support IPv6).
+Essentially the same way as IPv4 dynamic routing, simply alongside IPv4, for instance by running a BGP daemon for IPv4, and another one for IPv6. You can for instance have exactly the same peering policy (at least with your peers who support IPv6).
 ===== Does my IPv6 address leak information on my machine? =====
-If you configure your network with stateless configuration, and do not enable its privacy extension, yes, your IPv6 address will contain the MAC address of your network board, which happens to contain information about the manufacturer of the board, when, and where it was built (and thus roughly where it was sold).
+If you configure your network with stateless configuration, and do not enable its privacy extension, yes, your IPv6 address will contain the MAC address of your network board, which happens to contain information about the manufacturer of the board, when, and where it was built (and thus roughly where it was sold). For instance, in 2001:db8::1234:56ff:fe78:9abc/64, the 12:34:56:78:9A:BC MAC address shows up.
 But that's only in that case. With static configuration, dhcp dynamic configuration, or stateless configuration with privacy extension (i.e. it basically takes a random address), there is no such issue.
+The privacy extension is usually not enabled by default, but can be enabled this way on Linux (here on eth0):
+''echo 2 > /proc/sys/net/ipv6/conf/eth0/use_tempaddr''
+TODO: other OSes
 ===== Do I have to change all my equipments? =====
-No. All equipments which only talk L2 protocols such as Ethernet do not need to be changed: to them, IPv6 is just another kind of payload among others (86dd for IPv6 instead of 0x0800 for IPv4). The ethernet protocol itself is completely unchanged.
+No. All equipments which only talk L2 protocols such as Ethernet do not have to be changed: to them, IPv6 is just another kind of payload among others (0x86dd for IPv6 instead of 0x0800 for IPv4). The ethernet protocol itself is completely unchanged.
-Routers, however, might have to be changed if they are really old, because these have to talk IPv6.
+L3 routers, however, might have to be changed if they are really old, because those will have to talk IPv6.
 ===== Do I have to recode all my software? =====
@@ Ligne 257: / Ligne 292: @@
   * it does not deal with IPv4 addresses at all,
-  * and it uses IPv4/IPv6-agnostic programming interfaces, with a runtime that supports IPv6
+  * and it uses IPv4/IPv6-agnostic programming interfaces, with a runtime that supports IPv6.
+For instance, if your software just passes a (hostname,port) pair to its programming interface, the software does not need any modification. One has to make sure that the runtime behind the programming interface supports IPv6, of course. This is now the case for the vast majority of them (TODO: list them?)
-For instance, if your software just passes a (hostname,port) pair to its programming interface, the software does not need any modification. One has to make sure that the runtime behind the programming interface supports IPv6, of course. This is now the case for the vast majority of them.
+Most notably, the historical C network programming interface is not completely IPv4/IPv6-agnostic: ''gethostbyname'' does not return enough information to be able to not care about the differences between IPv4 and IPv6. ''getaddrinfo'' should be used instead, since it provides exactly what you have to give to ''socket'', ''bind'', and ''connect''.
-Most notably, the historical C network programming interface is not completely IPv4/IPv6-agnostic: ''gethostbyname'' does not return enough information to be able to not care about the differences between IPv4 and IPv6. ''getaddrinfo'' should be used instead, since it provides exactly what you have to give to ''socket'', ''bind'', and ''connect''
 ===== Can I still do XXX with IPv6? =====
@@ Ligne 270: / Ligne 306: @@
 ===== Is there ARP in IPv6? =====
-Yes, although it is rather called Neighbour Discovery Protocol (NDP) and works a bit differently (but basically it's the same principle).
+It was reworked and called Neighbour Discovery Protocol (NDP), and is contained in ICMPv6 instead of a special type of ethernet frame. In the end NDP is basically the same principle as ARP, to translate from L3 addresses to L2 addresses, but implemented in a better way.
 ====== Cheatsheet ======
@@ Ligne 279: / Ligne 315: @@
 ::1
+(i.e. 0::1)
+===== What is IPv6's 0.0.0.0? =====
+::
+(i.e. 0::0)
 ===== Which addresses can be used for local use? (i.e. equivalent of 192.168.0.0/16 etc) =====
@@ Ligne 288: / Ligne 332: @@
 ====== Some quick examples ======
+===== Firefox =====
+Out of the box, firefox should use IPv6 connectivity when available. However, it is not visible to the user.
+There is a firefox extension that displays whether the current page is loaded over IPv4 or IPv6: https://addons.mozilla.org/fr/firefox/addon/sixornot/
+You can test it on this wiki: if you have IPv6 connectivity, you should see a green "6" (loaded over IPv6). Otherwise, you will see an orange "6" (the wiki has IPv6 records in the DNS, but you are still reaching it over IPv4).
+If IPv6 connectivity does not work, make sure that it is not disabled: in ''about:config'' , make sure that ''network.DNS.disableIPv6'' is set to ''false''
 ===== Basic OS checks =====
@@ Ligne 344: / Ligne 397: @@
 TODO: how to deactivate ipv4 completely, to check ipv6 for sure?
+==== *BSD ====
+TODO
 ==== MacOS ====
@@ Ligne 387: / Ligne 444: @@
 To enable IPv6 in the tunnel, **TODO**.
 ==== TODO: more ====
 ===== radvd configuration example =====
@@ Ligne 394: / Ligne 453: @@
   interface eth0 {
     AdvSendAdvert on;
-    prefix 2001:db8:0:1::/64 { };  # enable stateless configuration
+    prefix 2001:db8:0:1::/64 { };  # enable stateless configuration within that prefix
     route ::/0 { };  # default route through us
     RDNSS 2001:db8:0:1::1 { };  # announce DNS server.
   }
-''RDNSS'' can optionally be dropped and a DHCPv6 server configured instead. ''prefix'' and ''route'' are still necessary to provide hosts with routing information (RA).
+''RDNSS'' can optionally be dropped and a DHCPv6 server configured instead. ''prefix'' and ''route'' are still necessary to provide hosts with routing advertisement (RA).
 ===== DHCPv6 configuration example =====
@@ Ligne 408: / Ligne 468: @@
 ===== dnsmasq =====
-dnsmasq can provide both DHCPv6 and Router Advertisement (RA)
+dnsmasq can provide both DHCPv6 and Router Advertisement (RA).
 TODO
 ===== Firewall example =====
-Here are example for home-use firewalls: connections only go from inside to outside, assuming a DSL connection to the Internet. It also accepts NDP (just like ARP is usually accepted), but makes sure it will not be forwarded (hop limit is 255).
+Here are examples for home-use firewalls: connections only go from inside to outside, assuming a DSL connection to the Internet. It also accepts NDP (just like ARP is usually accepted), but makes sure it will not be forwarded (hop limit is 255).
 ==== iptables ====
@@ Ligne 468: / Ligne 529: @@
 This gives examples of how to configure a DNS64 server in order to make client machines automatically use DNS64. One just needs to pick a /96 prefix among one's own addresses, or use the well-known 64:ff9b::/96 prefix, here we will use 2001:db8:0:1::/96 as example.
 ==== bind ====
@@ Ligne 485: / Ligne 547: @@
 RDNSS can also be used to announce the address of a DNS server. The use of a DHCPv6 server may still be useful, configuring it to not distribute IP address, but distribute other kinds of information, such as SMB network name, SMTP server name, etc.
 ===== Mobile IPv6 =====
-Although not widely used, this allows a machine to roam between IPv6 networks without losing your connections: the machine is carrying a public adress with it, attached to the home LAN of the machine, and packet routing to the machine is automatically done down to the network where the machine happens to go through.
+Although not widely used, this allows a machine to roam between IPv6 networks without losing connections: the machine is carrying a public adress with it, attached to the home LAN of the machine, and packet routing to the machine is automatically done down to the network where the machine happens to go through.
 ====== Why is there no IPv5? ======