Hi everyone,
Regarding Question 6 about Certificates in the network security homework, in sub-question 7 you should obtain the OCSP URL from the leaf certificate and the CRL distribution URL from the intermediate certificate. Then, in sub-question 8 use the CRL downloaded from the intermediate certificate.
Note that even if you see news that Let'sEncrypt no longer uses CRLs, the CRL distribution URL is available in the intermediate certificate and can be downloaded.
Best regards,
Juan
-- Juan Caballero Associate Research Professor IMDEA Software Institute Madrid, Spain