linux - Systemd-networkd: How can I prepend a static nameserver entry to DHCP-discovered nameservers?

I'm using systemd 213 on Arch Linux, and systemd-networkd/resolved with DHCP to connect to the internet. I'm also running a caching DNS server on 127.0.0.1. I'd like to make this server the first DNS server in the list, but I'd also like to use the nameservers discovered by systemd-resolved. Using a static resolv.conf isn't really possible, because I connect to networks with different DNS settings.

I know I can set fallback DNS servers in /etc/systemd/resolved.conf, but is there a way with systemd-networkd to prepend my local DNS server to those discovered by DHCP?

Edit: What I've tried so far

• Adding a manual DNS entry in the .network file results in that entry being appended instead of prepended:

  # This file is managed by systemd-resolved(8). Do not edit.
  #
  # Third party programs must not access this file directly, but
  # only through the symlink at /etc/resolv.conf. To manage
  # resolv.conf(5) in a different way, replace the symlink by a
  # static file or a different symlink.
  
  nameserver 141.48.3.51
  nameserver 141.48.3.17
  nameserver 141.48.3.3
  # Too many DNS servers configured, the following entries may be ignored
  nameserver 127.0.0.1
  

• If I add UseDNS=true in the [DHCPv4] section as well, as described in the systemd.network(5), manpage, the nameservers discovered by DHCP are ignored and only the static DNS entry is used, which is not what I want either:

  # This file is managed by systemd-resolved(8). Do not edit.
  #
  # Third party programs must not access this file directly, but
  # only through the symlink at /etc/resolv.conf. To manage
  # resolv.conf(5) in a different way, replace the symlink by a
  # static file or a different symlink.
  
  nameserver 127.0.0.1
  

• Using the in_addr representation for the DNS address just appends my nameserver, just like using the normal representation.

Have you tried adding these two lines:

  [Network]
  DNS=127.0.0.1

to one of the files /etc/systemd/network/*.network? For instance, for a dhcp client, modify /etc/systemd/network/80-dhcp.network to contain the lines:

  [Match]
  Name=en*

  [Network]
  DHCP=yes
  DNS=127.0.0.1

EDIT:

Have you tried the in_addr representation? Try substituting 127.0.0.1 with 16777343.