dhcpcd-discuss

On 2017-08-26 01:57, M. Buecher wrote:
> On 2017-08-25 20:50, Roy Marples wrote:
>
> > On 25/08/2017 17:40, harald.albrecht wrote:
> >
> > > Debian Stretch 9 has systemd-network enabled in full glory. Can 
> > > someone please explain how networkd and dhcpcd relate to reach other? 
> > > I'm still scratching my head!
> >
> > They're not related!
> >
> > However, you can run Debian without systemd the last time I checked, 
> > which also means no networkd either.
> >
> > Also, Debian (and also Ubuntu) act as package managers for other dpkg 
> > based distributions which may use something else such as 
> > NetworkManager or dhcpcd and dhcpcd-ui.
> >
> > Roy
>
> I use the Raspbian [1] release of the Raspberry Pi Founddation [2]
> which is a Debian derivative that uses dhcpcd in its releases.
>
> [1] https://www.raspbian.org/
> [2] https://www.raspberrypi.org/downloads/raspbian/
>
>
> I'm still using /etc/network/interfaces.d/ifcfg-ethernet for my IPv6
> static addresses for incoming connections and to enable Privacy
> Extensions for outgoing connections on "eth0".
> Works via systemd's fallback support of /etc/network/interfaces* on
> Debian/Raspbian.
> Reasons are...
> a) that I haven't got to systemd network configuration in my leisure
> time yet. Maybe it's dead simple and easy.
> b) the Debian package only includes dhcpcd 6.10.1 without "static
> ip6_address" or temporary addresses according to its man page.
>
>
> Goals I want to achieve with dhcpcd on my Raspbian server:
> a) ULA
> * Static ULA address (currently via
> /etc/network/interfaces.d/ifcfg-ethernet, due to old dhcpcd version)
>   The host is the DHCPv6 server for the managed ULA with
> dynamic+static DHCP addresses.
>
> b) GUA
> Prefixes are advertised by the FRITZ!Box router, delegated from the
> ISP German Telekom
> * Temporary GUA addresses for outgoing connections
> * Stable GUA address for services and to allow "port forwarding" on
> the FRITZ!Box router (prefix changes are already considered by the
> router)
>   * Idea was to use the same interface id from the ULA address (e.g.
> ::0:0:0:1), because it is easy to remember as already known from the
> ULA and does not provide any hardware informations.
>     Right now implementation needs a dhcpcd hook script to add this
> address for each advertised prefix.
>     Stable private addresses are only stable for the same
> network/prefix, so not useable with changing prefixes from the ISP.
>   * On a new prefix reload dnsmasq, so that it can assign new stable
> GUA addresses from its static DHCP pool to the other servers.
>     Implementation needs a dhcpcd hook script to reload dnsmasq.
>
>   * Unfortunately during my tests the FRITZ!Box always re-calculated
> the hardware-based address for the host :(
>     So for now I additionally need that old hardware-based stable
> address, until I get the router to accept my changes.
>     For testing it is helpful to have all possibile stable addresses 
> assigned.
>
> c) Do everything via dhcpcd as a "Single-Point-of-Contact"
>    Have already some other feature requests in mind related to my
> goals, but get the first one right, then do the others :)
>
> Maddes

Thanks to Harald I just checked out the systemd-networkd.service, it was 
easy and it already gave my the options to configure my IPv6 addresses 
as I want [2].
It supports static interface ids over changing prefixes via IPv6Token, 
so that I could configure my router accordingly.
Created a feature request T136 [1] to support this in dhcpcd too.

Still going to prefer dhcpcd as it supports DHCPv4 inform messages, so 
that when I temporally use my router's DHCP & DNS the host with its 
static IPv4 address is still reachable via its name.
Additionally I want to use the event-driven script calls to reload 
dnsmasq whenever the GUA prefix changes.

Maddes

P.S.:
Debian defaults to the ifupdown legacy compatibility networking.service 
instead of the "real(TM)" systemd-networkd.service.
 systemctl enable systemd-networkd.service
 systemctl disable networking.service
 systemctl stop networking.service ; systemctl start 
systemd-networkd.service

[1] https://dev.marples.name/T136
[2] /etc/systemd/network/eth0.network:
[Match]
Name=en*

[Network]
IPv6AcceptRA=yes
LinkLocalAddressing=ipv6
IPv6Token=::a:b:c:d
IPv6PrivacyExtensions=yes

## ULA
[Address]
Address=fd00:1:2:4:a:b:c:d/64