Fix IP address for Repetier Server (LAN) instead DHCP, how?

Topsurfer

Hi,
actuall my RepetierServer ist connected by LAnd and is using DHCP.

Now I want to change to fix IP address, because all "Linux" systems should be in my defined IP range ;-)

I habe little bit knowledge on linux and most of my systems are running fix IP addresses.

But here the /etc/network/interfaces exists but only has:

# Include files from /etc/network/interfaces.d:

source-directory /etc/network/interfaces.d

And the folder  /etc/network/interfaces.d  is empty ....

What have I add where to use a fix IP address for LAN ?
Deactivate the DHCP service also?

Repetier

Better solution is to check the mac address (you see it in home screen of server) and make your route assign it always same ip based on mac. That is how you do it normally so devices keep their IP. 

Otherwise check dhcp server which ips are not controlled by dhcp to prevent a conflict, go to Global Settings->Network->Wired Connection and change IP V4 from automatic to the manual values you enter. Be careful - with wrong values you might get problems connecting. Save and it should switch to your settings.