Truststore File
Integration Server uses a truststore to store its trusted root certificates, which are the public keys for the signing CAs. Although a truststore can contain the trusted roots for entire certificate chains, there is no requirement for the organization of certificates within an Integration Server truststore. It simply functions as a database containing all the public keys for CAs within a specified trusted directory.
If a partner uses certificates signed by a private CA, the certificates need to be included in a truststore.