If I use a VPN, who will resolve my DNS requests?
Will they be resolved by my VPN provider, or by my original ISP (if left on "automatic" settings)? Would I have to manually configure a dns server, to make sure my requests will not be resolved by my ISP (constituting a privacy risk)?
The requests will be passed to the IP that's configured. So if your DNS is still your ISP's DNS, then yes you will still be asking your ISP to resolve a domain name for you.
Windows Vista has an "automatic" setting, the default setting for finding a domain name server (no ip is explicitly set with this setting). If left on automatic, do you think this would mean any dns requests go to my ISP?
I would just set an explicit IP, I don't know what would happen if you use the automatic setting. It might be you do get a new DNS configuration if the VPN provider sends you one when you request an IP. Just test it I guess :)
@Samuel Yes. If you have a standard set up: Router using DHCP then 'automatic' will obtain a DNS server over DHCP which will point to your local router, your local router will then use your ISPs DNS servers for DNS lookups.
What if the VPN tunnel is a virtual interface with it's own DNS configuration? How would the Windows OS's choose DNS server? For Linux, I assume the /etc/resolv.conf will be updated with the newest interface...
Can I do the opposite? I mean, create a VPN only for processing DNS queries (basically, to block ads). While the traffic goes directly to my ISP. Thanks.