DNS Suffix on two network Interfaces on MacBook Pro

Hello,

I got a new MacBook Pro for my work office and have a network issue.

On the MBP 13" I use the integrated Wifi and an additional a Belkin USB ETH.

Now, with those two network interfaces I connect to two different networks:

a) Work network (WIFI)

b) Test network (ETH)

From both networks I get an IP via DHCP incl. DNS server address and search domain / suffix:

a) DNS Server 10.10.10.10

a) Search domain .intern

b) DNS Server 172.16.30.1

b) Search domain home

Right now the ETH (b) is on top of the list:

If I now want to connect (ping) to a device in test network (b) it works:

ping ubuntu.work

But If I try to connect (ping) to a device in the company network (a) it doesn't work:

ping server.intern

I tried to switch the order of the devices (first WIFI, second ETH) and then the issue swaps around (now .intern works but .work not anymore). For me it seems that Mac OS is sticky to the first (main?) network interface. I also tried to set the test network (ETH - when on top of the adaptor list) to manual IP and to leave the DNS server / search domain empty, but even then the DNS from the second device (Wifi) will not be used.

Does anyone have a solution for that?

Can't be that I am the first one to come over that issue 😉

Thanks a lot

Stefan