Hi Rob,
when I run
openssl x509 -text -in /var/kerberos/krb5kdc/kdc.crt
I get output containing the lines:
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 3 (0x3)
Signature Algorithm: sha256WithRSAEncryption
Issuer: O=NET.IDA, CN=ipa1.ida.ing.tu-bs.de
Validity
Not Before: Sep 28 09:51:09 2020 GMT
Not After : Sep 28 09:51:09 2021 GMT
Subject: O=NET.IDA, CN=ipa1.ida.ing.tu-bs.de
<...>
Looks ok to me.