network (with defined IPs) in another network (with DHCP) - connection issues

Question

We develop a client-server application where the server needs to be available with a known IP-address. Therefore, we configure router and PC with defined IP-addresses. This works fine, as long as everything is at the customers place.

If the hardware is connected to our office network, everything breaks after a time, because we have a DHCP that automatically assigns IP-addresses.

Is there a way to have a network inside our DHCP network where some devices have defined IP-addresses? We would like to prepare PC and router with fixed addresses and still be able to connect them to our network. What is an official term for this I could search for?

Update

Our network A (with defined IPs in range 192.168.0.XXX) contains two PCs, a switch and and access point for WiFi. In network B (there is DHCP setting IPs in the range 192.168.1.XXX). We could not find an explicit "ignore" function, but since the DHCP is applied 192.168.1.20 to 192.168.1.200, I think the IPs of 192.168.0.XXX should be ignored. Connecting the switch of network A to our network B allows us to go online in network A with a couple of connection issues.

Answer 1

All devices of network A (with defined IPs) have to be in the same sub network, but in a range that is skipped by the DHCP of network B. Make sure to disable DHCP in the access point.

• Example network A:

  • Access Point: 192.168.1.1
  • PC 1: 192.168.1.2
  • PC 2: 192.168.1.3

• DHCP range in network B: from 192.168.1.50 to 192.168.1.200

• Standard gateway and DNS IP had to be set for network A for instance like this:
  • 192.168.1.254 (coming from network B)

Configuration that did not work (or had connection issues):

• Example network A:
  • Access Point: 192.168.0.1
  • PC 1: 192.168.0.2
  • PC 2: 192.168.0.3 I assume, because it was a different sub network.