Hello regis,
Thanks a lot. It is exactly what I am looking for.
But could you please shed more light on it? Both custom and netlify subdomain points to the same files.
Your method basically generates two robots.txt files for both of them, right?
Then it could automatically switch between these two robots.txt files based on the traffic entry?
I will do the test by myself, and I want to know how it exactly works.
Cheers