OK, you can not edit the virtual adapters of VMware Fusion in the GUI. I believe this is/was possible with VMware Workstation. But you can edit its pref file which is located at
/Library/Preferences/VMware Fusion/networking
I first tried to set both adapters to no dhcp according to this blog post: http://blog.jameskyle.org/2013/05/disable-dhcp-daemon-on-default-vmnets-in-vmwar e-fusion-5/
But this didn’t suffice. As long as Fusion was running these 2 IPs showed up again in Server.app even though I could see that now both vmnet-dhcpd processes were not running. I then just disabled both vmnet adapters which did the trick and does not affect my VM. The file now looks like this (changes in red):
VERSION=1,0
answer VNET_1_DHCP yes
answer VNET_1_DHCP_CFG_HASH 9D7B8E993A2CA944BDD3D2415820EE8CE010A8F2
answer VNET_1_HOSTONLY_NETMASK 255.255.255.0
answer VNET_1_HOSTONLY_SUBNET 192.168.145.0
answer VNET_1_VIRTUAL_ADAPTER no
answer VNET_8_DHCP yes
answer VNET_8_DHCP_CFG_HASH 4AF3F1A17D543878A20398370780068EBE32200A
answer VNET_8_HOSTONLY_NETMASK 255.255.255.0
answer VNET_8_HOSTONLY_SUBNET 192.168.94.0
answer VNET_8_NAT yes
answer VNET_8_VIRTUAL_ADAPTER no
add_bridge_mapping en0 2
I am posting this here in order to find it again, should I ever forget about my changes and need the vmnet adapters.
Thanks for your help, both of you!
Björn