Netctl undocumented features
I use netctl to configure my network interfaces. While some features seem to be missing, here is a list of some useful features that are supported by the tool but not documented:
Passing options to your DHCP client
Although currently, only dhclient and dhcpcd are officially supported, it still seems quite a pain to pass them custom parameters without using the environment.
Some people suggest to use the DHCPClient variable to pass the name of the binary along with their options.
Nonetheless, it is possible to use the variables DhcpcdOptions or DhclientOptions.
Example (here, we pass a custom hostname and a custom metric to dhcpcd:
> DhcpcdOptions='-h hostname -m metric'