We have been using an Exchange 2010 mail server for a year now. Today the certificates used in Exchange, as well as of Forefront TMG expired.
We had the following certificate chain: Root CA issued a sub CA a certificate that has expired today as well.
SubCA issued a whole bunch of certificates (in the issued list), but from what I understand, the main is CSPO and CA certificate.
I have access to all servers in pay for mailflow: RootCA, SubCA, Exchange, Forefront.
What will be the outline of actions I need to take, to get back the mail running?