I use in my home-network a Pi-Hole for ad-blocking.
When I connect to our company VPN, the ads are back.
Because the company router as DNS-resolver is transmitted from the server (SSTP for clarification).
Its exact the same as described here: viewtopic.php?t=83843
As described in the other thread, if the DNS-server field (PPP -> Profiles) is empty/blank. there is always a DNS transmitted (I assume this is the standard behaviour).
But I found a simple solution, just use 255.255.255.255 as the DNS entry:
This results in no inserted DNS-entry:
For confirmation, if the DNS-server-field in the profile is empty (or 0.0.0.0 is used):
The DNS is inserted:
Unfortunately, this works only with Windows-Clients. Linux/Android-Clients receive and use the 255.255.255.255 as DNS.
In this case, use the "ignore pushed DNS servers" option if available.
If you know another option to suppress the DNS, let me know.