commands for checking TLS certs

TLS-check

# CAfile trusts a given CA cert for this call
# should return 0
# Certificate chain is presented:
# Number on left represents depth
# example.com is the first subject i.e. the host we are contacting
# and its issuer is Fake LE Intermediate X1
# the next cert on the chain has its subject as Fake LE Intermediate X1
# and its issuer is Fake LE Root X1
# which is the root of the chain i.e. a Certificate Authority
# 
# Certificate chain
#  0 s:/CN=example.com
#    i:/CN=Fake LE Intermediate X1
#  1 s:/CN=Fake LE Intermediate X1
#    i:/CN=Fake LE Root X1
openssl s_client [-CAfile <ca-file>] [-showcerts] -connect <host>:443

# reading certs 
openssl x509 -in <file> -out -notext

# converting cert formats:
openssl x509 -in <file> -inform <der|pem|net> -outform <der|pem|net> -out <file>

# curling with a inline CA file

curl --cacert <certfile.pem> https://:host