I just didn't know what an external switch is. I guess is the equivalent of VMware giving direct connection to the network adapter, not NAT. I didn't mean to judge you.
Foir clarity, I will try and explain the difference between an external and default switch (I think you understand but there are some subtleties that one should understand).
First imagine a physical pc where you have one router connected to internet, and pc is connected to router. Now imagine you have a second pc connected via a second router which is connected to first router via an ethernet cable via lan ports.
For the second router to talk bidirectionally to the first router, its IP address has to be on the same subnet (also DHCP should be turned off on second router).
There is only one NAT firewall between the 1st router and internet. By connecting the second router via a lan port, you are bypassing the second routers NAT.
Essentially a Hyper-V external switch is the virtual equivalent of connecting a second physical router via LAN ports.
The host machine can talk to the guest vm in just the same way as any pcs on a network with same subnet.
The default switch is different - it is analagous to the second router being connected to the first router via an ethernet cable connecting a LAN port on first router to the WAN port on second router). In a physical network, the second router would be behind a second NAT firewall with a separate IP subnet.
There are pros and cons of using an external switch vs default switch.
The vm using a default switch is easy to set up and is somewhat more secure as it is behind its own firewall. An internet hacker would need to get through two firewalls to hack the vm. The downside is it is not easy to network between the vm and host if that is required. Also, if you need to use port forwarding (some games need that), it is very difficult to do on vm requiring quite complicated powershell scripts.
For most cases e.g. testing an Insider version, I just stick with the default switch as I never need port forwarding on vm. Only slight downside is you cannot use rdp to connect to vm - you have to use the hyper-V manager (vmconnect). If you have say two network users connected to router, the second user cannot easily connect to the vm as they would not even be able to see it or even ping it.
An external switch allows easy connection via rdp but is less secure perhaps. If there were two users connectect to host router, they could both rdp to vm
(not at same time) and depending on password setup, have unauthorised access.
So my general advice is to always use the default switch UNLESS you have a good reason to put the vm on the same subnet as the host router using an external switch.
Note: the default switch was a later addition to Hyper-V. A lot of websites do not even mention it!
Regarding network adapter access, Hyper-V does not really work like VMWARE being a type 1 hypervisor but that is a whole different story.
