Re: NM bug 684242 and other stuff

[Pavel Simerda <psimerda redhat com>]

I'll divide my reaction into four parts and post it also to NM mailing list so that anyone can
benefit.

1) DHCPv6 currently works according to IETF standards and has been tested with NetworkManager
commit 70f64fbc4277c636c0a373d6e6eddf0574d53827 before merging the 'ipv6' branch into
master. The problem with setting default route has been fixed in the previous commit
70f64fbc4277c636c0a373d6e6eddf0574d53827. You can look at them for more details.

I have just checkout out 0.9.6.0, ran ./autogen.sh, make, make install and ran NetworkManager.

DHCPv6 works like a charm including RA-originated default route. It even works without any
configuration (just delete it or move it away).

# ip address show dev eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:eb:e9:fb brd ff:ff:ff:ff:ff:ff
    inet 192.168.25.12/24 brd 192.168.25.255 scope global eth1
    inet6 2001:abcd:1:1::1:115b/128 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:feeb:e9fb/64 scope link 
       valid_lft forever preferred_lft forever

# ip -6 route show default
default via fe80::5054:ff:fe44:5d16 dev eth1  proto static  metric 1 
default via fe80::20c:42ff:fe13:857b dev eth0  proto kernel  metric 1024  expires 57sec
default via fe80::5054:ff:fe44:5d16 dev eth1  proto kernel  metric 1024  expires 252sec

The routes with metric 1024 are from kernel. NetworkManager wants to make eth1 the default
interface so it creates the same route with metric 1.

The testing server environment is as described in:

https://fedoraproject.org/wiki/Tools/NetworkManager/IPv6#DHCPv6_address_and_DNS_configuration

I'm doing first tests with firewall and selinux disabled (if applicable). If your tests show
different results, please present them in their full beauty.

2) NetworkManager supports the following methods:

method=auto (this is the automatic configuration described in IPv6 standards including DHCPv6)
method=manual (you can set up addresses here)
method=link-local (global addressing is disabled)

It doesn't currently support all sorts of hybrids. If you want it to support something more than
autoconf (including DHCP) and manual configuration, please file a RFE in bugzilla (if it's not
filed already).

Don't use method=dhcp (aka DHCP only). It never worked.

Don't use method=ignore, it was there to leave everything up to the kernel when NetworkManager
didn't have such good support for IPv6.

3) http://tools.ietf.org/html/draft-ietf-mif-dhcpv6-route-option-03

This draft is recycling something that has been proposed for *years*. In my opinion, there is no
need to care about this at all at this point of time. I think mostly only need to care about
the current IPv6 node requirements:

http://tools.ietf.org/html/rfc6434

This is what you can expect from IPv6 configuration daemon. If this document is updated/obsoleted,
then there's time for implementing the change in NetworkManager. Unless, of course, you have a very
good reason to do otherwise.

4) Looking forward to seeing your IPv6 dynamic DNS patch merged. Even though I'm not using dyndns at
all, I'm glad that you are trying to make IPv6 work like IPv4 did for you.