Question: resolving without chaining?

[MatthiasLohr]

Hi,

when I try to resolve the A record of a hostname (e.g., account.google.com) which actually does not have an A, but a CNAME record, dns.resolver.resolve still returns a A record (due to "chaining" I guess). How can I check if there is actually a CNAME or a A record set for this domain?

Best regards
Matthias

[rthalley]

Try this:

import dns.resolver

answer = dns.resolver.resolve("account.google.com")
if answer.qname != answer.canonical_name:
    print(f"chaining occurred for {answer.qname}")
    print(f"the end of the chain was at {answer.canonical_name}")

[rthalley]

You can also query for a CNAME explicitly, which won't chain, though I prefer the first solution above.

import dns.resolver

try:
    answer = dns.resolver.resolve("account.google.com", "CNAME")
    print(answer.rrset)
except Exception:
    print("no CNAME")

[MatthiasLohr]

I want to do both, check for CNAME (works) and A and AAAA. For A and AAAA, I was not able to check there is actually a A/AAAA record or if it is chained reply, but now it's clear I think. Thanks!