Is there a way to know the server url and protocol used ?

[abhitrip07]

Below is an output from dig

$ dig +https @dns.google youtube.com

; <<>> DiG 9.20.7 <<>> +https @dns.google youtube.com
; (4 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60965
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;youtube.com.			IN	A

;; ANSWER SECTION:
youtube.com.		300	IN	A	142.251.222.174

;; Query time: 32 msec
;; SERVER: 2001:4860:4860::8844#443(dns.google) (HTTPS)
;; WHEN: Wed May 28 11:54:22 IST 2025
;; MSG SIZE  rcvd: 56

I want to know if dnspython has a utility method to return the server URL (dns.google) and the protocol used (HTTPS). This is so I can ensure that the server is actually responding to what the client has asked.

[rthalley]

Yes, the Answer object from resolver methods, e.g. dns.resolver.resolve() has a nameserver attribute which is the IP address of the nameserver which answered the query for non-HTTP-based queries, and the URL for HTTP-based queries.

[abhitrip07]

We are following the doh example and wrote this:

    with httpx.Client() as client:
        q = dns.message.make_query(domain, dns.rdatatype.A)
        r = dns.query.https(q, doh_url, session=client)
        for answer in r.answer:
            print(answer)

Is it possible to get the "nameserver" in the https response object? I checked that the response from https() is a Message object which does not have "nameserver", so I am guessing the answer is NO.

[rthalley]

I'm confused; in this case you know the URL and are specifying the transport (HTTPS). Do you want to know the IP address of the server actually used? If so see stackoverflow

[abhitrip07]

Yes, I know the URL. Sorry if I was not clear. Let me give a little background.

We have our own custom DNS resolver service. So far, we have been supporting UDP & TCP. Now we have added support for DOH. So I want to ensure from the response of our DNS server that it actually used HTTPS and not UDP/TCP. More than the URL/IP, I am interested in the protocol used as specified in the dig response above.

That's the whole point of checking if it is possible from dnspython. If not we will rely on our service logs.

[rthalley]

dns.query.https() will only use HTTPS, so just by using it you can be sure. If you care about HTTP versions, you can say http_version=dns.query.HTTPVersion.H2 to do a TCP query using HTTP/2 with TLS, or http_version=dns.query.HTTPVersion.H3 to do an HTTP/3 query using QUIC. You must have aioquic installed for QUIC to work.

[abhitrip07]

Thanks for your responses @rthalley. Appreciate it.