The Alert Logic® Decrypter (ALD) is a component within the Alert Logic Threat Manager™ appliance that decrypts network traffic. All TCP traffic must be observed for decryption to succeed.
If your SSL certificates are expired, the Alert Logic Decrypter will ignore the expiration dates. If the Alert Logic Decrypter sees traffic that makes use of an expired certificate, it will still use the corresponding private key to decrypt traffic.
You can install many certificates on your appliance. The limitation on the number of certificates you can install per appliance is determined by available memory. However, certificates have to be looked up during TLS handshakes. Consequently, having a large number of certificates loaded can impact performance.