[systemd-devel] [networkd] Mixing DHCP & static IPs on 1 interface

[Reindl Harald]

Am 22.02.2017 um 01:30 schrieb Ian Pilcher:
> I'm trying to find a way to do this with systemd-networkd.
>
> The reason is that my cable modem listens on a 192.168.X.X address.
> Normally this "just works".  My firewall tries to send traffic destined
> for this address to my ISP's router, and the cable modem intercepts the
> packets and responds.
>
> If I lose connectivity, however, my firewall doesn't have a default
> route, so it doesn't know where to send packets destined for
> 192.168.X.X.  The net result is that I lose connectivity to my cable
> modem's diagnostic pages at exactly the time that I need to access them.
> (OK, I don't really lose connectivity; I just have to manually add an
> IP address on the proper subnet to the firewall's external interface.
> It works, but it's so ... MANUAL!  :-)

since this should be all on the LAN side something is *very* unusual on 
your setup - the firewall i setup at office is just a virtual machine 
with a single NIC and is able to do NAT and filtering as well as 
traffic-shaping (limit all workstations together to 80% of the WAN line) 
with a single IP address - so i don't see any reason why your firewall 
can't forward packages to your router independent of the WAN state on 
the other side of the router