win: don't (always) set DNS with the adapter

Reverts the changes done in commit e6e7b91. Turns out this is actually
not needed for search domains to work. That is what recent tests
confirm, even though tests back then told a different story.

Not having the DNS set has the advantage that no search domains are
leaked to the VPN DNS provider when in split mode. Only configured
domains will be handled by the NRPT rules, the others go a different
way.

Jira: OVPN3-1444
Signed-off-by: Heiko Hund <heiko@openvpn.net>

Author: d12fk

openvpn/tun/win/client/tunsetup.hpp

@@ -723,9 +723,12 @@ class Setup : public SetupBase
                     create.add(new NRPT::ActionCreate(pid, split_domains, addresses, wide_search_domains, dnssec));
                     destroy.add(new NRPT::ActionDelete(pid));
                 }
-
-                // Set pushed DNS servers with the adapter
-                set_adapter_dns(create, destroy, tap_index_name, addresses, pull);
+                else if (allow_local_dns_resolvers && pull.block_outside_dns)
+                {
+                    // Set pushed DNS servers with the adapter. In case the local resolver
+                    // doesn't work the VPN DNS resolvers will serve as a fallback
+                    set_adapter_dns(create, destroy, tap_index_name, addresses, pull);
+                }
 
                 create.add(new DNS::ActionCreate(tap.name, search_domains));
                 destroy.add(new DNS::ActionDelete(tap.name, search_domains));