Networking/Ideas/NetworkManagerMethods: Difference between revisions

Revision as of 09:42, 19 October 2013

IPv6: Automatic global address needs link-local address
Gateway needs a manual address (at least a default one), conflicts with dynamic address

Method	Protocol	Link-local	Manual	Automatic	Gateway
disabled	IPv4	none	forbidden	none	none
ignore	IPv6	kernel	forbidden	kernel	none
link-local	IPv4	userspace	forbidden	none	none
link-local	IPv6	kernel	forbidden	none	none
manual	IPv4	none	required	none	none
manual	IPv6	kernel	required	none	none
auto	IPv4	none	allowed	dhcp	none
auto	IPv6	kernel	allowed	ra+dhcp	none
dhcp	IPv6	kernel	allowed	dhcp	none
shared	IPv4	none	?	none	dhcp+dns+NAT

Even when IPv4 is in the disabled state, the network interface communicates on the L2 level.
There's no disable method for IPv6 and its semantics is unclear (whether disable means the same as link-local, or it also applies to the link-local address which is unaffected in all other methods).
The usage of IPv4 and IPv6 link-local addresses substatially differs. While IPv6 uses link-local addresses for *all* methods, IPv4 only uses it for the special link-local method.
The IPv4 disable and IPv4/manual methods only differ in the number of addresses (0 versus >=1), therefore one of them is redundant.
The IPv6 link-local and IPv6/manual methods only differ in the number of addresses (0 versus >=1), therefore one of them is redundant.
The IPv6 dhcp method is currently defunct.
There's no IPv6 shared method, yet.

L	M	A	G	IPv4	IPv6	notes
no	no	no	no	disabled	unsupported	kernel's disable_ipv6 buggy
no	no	no	yes	invalid	invalid	missing manual address
no	no	yes	no	auto	invalid	missing IPv6 link-local address
no	no	yes	yes	invalid	invalid	missing manual address
no	yes	no	no	manual	unsupported	missing kernel feature
no	yes	no	yes	shared	unsupported	missing kernel feature
no	yes	yes	no	auto	unsupported	missing kernel feature
no	yes	yes	yes	invalid	invalid	both sides of dynamic configuration
yes	no	no	no	link-local	link-local
yes	no	no	yes	invalid	invalid	missing manual address
yes	no	yes	no	unsupported	auto
yes	no	yes	yes	invalid	invalid	missing manual address
yes	yes	no	no	unsupported	manual
yes	yes	no	yes	shared	unsupported
yes	yes	yes	no	unsupported	auto
yes	yes	yes	yes	invalid	invalid	both sides of dynamic configuration

There's a bug in the kernel (found by Dan Winship) that once setting IFF_UP with disable_ipv6=1 affects future state. But we shouldn't need disable_ipv6 just as we don't need disable_ipv4, see the next note.
Kernel doesn't support turning link-local addressing on/off (without affecting other features).

@@ Line 55: / Line 55: @@
 === Feature combinations ===
 {|
 !L!!M!!A!!G!!IPv4!!IPv6!!notes
@@ Line 62: / Line 61: @@
 |- style="color: grey"
 |no||no||no||yes||invalid||invalid||missing manual address
-|- style="color: green"
+|- style="color: blue"
 |no||no||yes||no||auto||invalid||missing IPv6 link-local address
 |- style="color: grey"
@@ Line 78: / Line 77: @@
 |- style="color: grey"
 |yes||no||no||yes||invalid||invalid||missing manual address
-|- style="color: blue"
+|- style="color: brown"
 |yes||no||yes||no||unsupported||auto||
 |- style="color: grey"
 |yes||no||yes||yes||invalid||invalid||missing manual address
-|- style="color: blue"
+|- style="color: brown"
 |yes||yes||no||no||unsupported||manual||
-|- style="color: blue"
+|- style="color: brown"
 |yes||yes||no||yes||shared||unsupported||
-|- style="color: blue"
+|- style="color: brown"
 |yes||yes||yes||no||unsupported||auto||
 |- style="color: grey"