[systemd-devel] DHCP Server on multiple interfaces

[Reindl Harald]

Am 17.10.19 um 17:55 schrieb Martin Townsend:
> Does systemd support the networkd DHCP Server on multiple network
> interfaces.  I ask as we have an embedded system running systemd 239
> and we want to configure a DHCP server on a bluetooth PAN and one of
> the Ethernet interfaces both of which are used for configuring the
> device.
> 
> I've set up both the network files with
> [Network]
> ....
> DHCPServer=yes
> 
> [DHCPServer]
> PoolOffset=10
> PoolSize=10
> DefaultLeaseTimeSec=12h
> MaxLeaseTimeSec=24h
> 
> When trying to connect to the bluetooth PAN I get
> Oct 17 15:28:39 vasig-imx6ul-txul-emmc systemd-networkd[307]: Failed
> to determine timezone: Invalid argument
> Oct 17 15:28:39 vasig-imx6ul-txul-emmc systemd-networkd[307]: pan0:
> Could not start DHCPv4 server instance: Device or resource busy
> Oct 17 15:28:39 vasig-imx6ul-txul-emmc systemd-networkd[307]: pan0: Failed
> 
> The message " pan0: Could not start DHCPv4 server instance: Device or
> resource busy" seems to suggest that only one server instance is
> allowed.  Weirdly the device connecting did get an ip address.  But if
> I look at the status of the pan0 I see:
> 
> root at vasig-imx6ul-txul-emmc:~# networkctl status pan0
> ● 4: pan0
>        Link File: /lib/systemd/network/99-default.link
>     Network File: /etc/systemd/network/30-pan0-bridge.network
>             Type: bridge
>            State: routable (failed)
>           Driver: bridge
>       HW Address: 82:2f:45:2a:9c:5a
>          Address: 192.168.10.1
> 
> eth0 is named such that it should be configured before the pan0

why would you listen on a bridge and additionally on a interface? you
use a bridge like a ordianry interface and every interface connected to
the bridge is in the same layer

Network bridge:
A bridge is a piece of software used to unite two or more network
segments. A bridge behaves like a virtual network switch, working
transparently (the other machines do not need to know or care about its
existence). Any real devices (e.g. eth0) and virtual devices (e.g. tap0)
can be connected to it.