Configure how are DoH3 server addresses resolved

[mon-jai]

My college's WiFi blocks DNS requests that aren't using its dedicated DNS server. DoH3 should, in theory, bypass this blockage, but it currently doesn't because DNSNet couldn't initially query the IP address for the DoH3 server.

This could be solved if there were an option to use the network's DNS to resolve the DoH3 server's address.

[mon-jai]

It would also help if DNSNet could cache the resolved address for DoH3 servers, making subsequent queries faster. Otherwise, there would be a one-DNS query overhead for subsequent DNS requests after the previous QUIC connection to the DNS server times out.

[stephen0z]

My college's WiFi blocks DNS requests that aren't using its dedicated DNS server. DoH3 should, in theory, bypass this blockage, but it currently doesn't because DNSNet couldn't initially query the IP address for the DoH3 server.

This could be solved if there were an option to use the network's DNS to resolve the DoH3 server's address.

Many DNS sites have published their IP address together with their query URLs. Therefore no need to query their server's IP addresses before sending any query URL.

However I don't find a way to input IP address in DNSNet. It only has the query URL available.

Maybe it is implemented with special input format.

[t895]

My college's WiFi blocks DNS requests that aren't using its dedicated DNS server. DoH3 should, in theory, bypass this blockage, but it currently doesn't because DNSNet couldn't initially query the IP address for the DoH3 server.

This could be solved if there were an option to use the network's DNS to resolve the DoH3 server's address.

That's odd. I don't use your custom servers when resolving the initial request. I just make a request to the system DNS resolver which uses your network's DNS servers.

I'm not aware of any weird implementation details with this call to resolve a given address either so I'm not sure what's going on exactly.

DNSNet/service/libnet/src/validation.rs

Line 104 in 92bae7b

let socket_addresses = match url.socket_addrs(|| Some(53)) {

It would also help if DNSNet could cache the resolved address for DoH3 servers, making subsequent queries faster. Otherwise, there would be a one-DNS query overhead for subsequent DNS requests after the previous QUIC connection to the DNS server times out.

Yeah I've been meaning to cache this somehow. I'm currently working on a cache for requests in general so I'll probably work on that soon.

Many DNS sites have published their IP address together with their query URLs. Therefore no need to query their server's IP addresses before sending any query URL.

However I don't find a way to input IP address in DNSNet. It only has the query URL available.

Maybe it is implemented with special input format.

There is currently no way to input the address alongside the query URL. I guess I can see a privacy improvement if you don't have to resolve the address of a DoH server every time you want to use it. So I could try to add an extra field for each server in an update.

Edit - On second thought, it won't actually affect privacy. But still it could be helpful to avoid repeatedly resolving addresses. Again, I'll consider it.

[mon-jai]

There is currently no way to input the address alongside the query URL.

Turns out https://1.1.1.1/dns-query, though not documented by Cloudflare, is a valid DNS resolver. There is a SAN (Subject Alternative Name) field in CA-issued certificates that verifies IP addresses someone owns: https://g.co/gemini/share/40af4514cb6e

Weirdly enough, https://1.1.1.1/dns-query is still blocked by my college's WiFi network. I'm sure it's not an IP ban, since I can access the URL from my browser, which returns a 400 status with no content.