Configuring Common Secure Interoperability Version 2 inbound communications

Inbound communications refers to the configuration that determines the type of accepted authentication for inbound requests. This authentication is advertised in the interoperable object reference (IOR) that the client retrieves from the name server.

1. Start the administrative console.
2. Click Security > Global security.
3. Under RMI/IIOP security, click CSIv2 inbound communications.
4. Consider the following layers of security:
   • Identity assertion (attribute layer).

     When selected, this server accepts identity tokens from upstream servers. If the server receives an identity token, the identity is taken from an originating client. For example, the identity is in the same form that the originating client presented to the first server. An upstream server sends the identity of the originating client. The format of the identity can be either a principal name, a distinguished name, or a certificate chain. In some cases, the identity is anonymous. It is important to trust the upstream server that sends the identity token because the identity authenticates on this server. Trust of the upstream server is established either using Secure Sockets Layer (SSL) client certificate authentication or basic authentication. You must select one of the two layers of authentication in both inbound and outbound authentication when you choose identity assertion.

     The server ID is sent in the client authentication token with the identity token. The server ID is checked against the trusted server ID list. If the server ID is on the trusted server list, the server ID is authenticated. If the server ID is valid, the identity token is put into a credential and used for authorization of the request.

     

     Note: If your configured registry is a Local OS, then the trust is instead established by checking if the upstream server identity is authorized on the downstream server with UPDATE authority to the CBIND class, profile CB.BIND.<optionalSAFProfilePrefix>.<cluster_short_name>. The upstream server identity is sent using an SSL client certificate. If SSL is not used, the CBIND check is performed against the started task identity of the upstream server.
     Note: When identity assertion is enabled, message layer or transport layer should be enabled also. For server-to-server communication, besides enabling transport layer/client authentication, identity assertion, or message layer should be enabled also.

     For more information, see Identity assertion.

   • Message layer:

     Basic authentication (GSSUP):

     This type of authentication is the most typical. The user ID and password or authenticated token is sent from a pure client or from an upstream server. When a user ID and password are received at the server, they are authenticated with the user registry of the downstream server.

     Lightweight Third Party Authentication (LTPA):

     In this case, an LTPA token is sent from the upstream server. If you choose LTPA, then both servers must share the same LTPA keys

     Kerberos (KRB5):

     To select Kerberos, the active authentication mechanism must be Kerberos. In this case, a Kerberos token is sent from the upstream server.

     For more information, read about Message layer authentication.

   • Secure Sockets Layer client certificate authentication (transport layer).

     The SSL client certificate is used to authenticate instead of using user ID and Password. If a server delegates an identity to a downstream server, the identity comes from either the message layer (a client authentication token) or the attribute layer (an identity token), and not from the transport layer through the client certificate authentication.

     A client has an SSL client certificate that is stored in the keystore file of the client configuration. When SSL client authentication is enabled on this server, the server requests that the client send the SSL client certificate when the connection is established. The certificate chain is available on the socket whenever a request is sent to the server. The server request interceptor gets the certificate chain from the socket and maps this certificate chain to a user in the user registry. This type of authentication is optimal for communicating directly from a client to a server. However, when you must go downstream, the identity typically flows over the message layer or through identity assertion.

     A client has an SSL client certificate that is stored in the key ring file of the client configuration. When SSL client authentication is enabled on this server, the server requests that the client send the SSL client certificate when the connection is established. The certificate chain is available on the socket whenever a request is sent to the server. The server request interceptor gets the certificate chain from the socket and maps this certificate chain to a user in the user registry. This type of authentication is optimal for communicating directly from a client to a server. However, when you have to go downstream, the identity typically flows over the message layer or through identity assertion.

5. Consider the following points when deciding what type of authentication to accept:
   • A server can receive multiple layers simultaneously, so an order of precedence rule decides which identity to use. The identity assertion layer has the highest priority. The message layer follows, and the transport layer has the lowest priority. The SSL client certificate authentication is used when it is the only layer provided. If the message layer and the transport layer are provided, the message layer is used to establish the identity for authorization. The identity assertion layer is used to establish precedence when provided.
   • Does this server usually receive requests from a client, from a server, or both? If the server always receives requests from a client, identity assertion is not needed. You can choose either the message layer, the transport layer, or both. You also can decide when authentication is required or supported. To select a layer as required, the sending client must supply this layer, or the request is rejected. However, if the layer is only supported, the layer might not be supplied.
   • What kind of client identity is supplied? If the client identity is client certificates authentication and you want the certificate chain to flow downstream so that it maps to the downstream server user registries, identity assertion is the appropriate choice. Identity assertion preserves the format of the originating client. If the originating client authenticated with a user ID and password, a principal identity is sent. If authentication is done with a certificate, the certificate chain is sent.

     In some cases, if the client authenticated with a token and a Lightweight Directory Access Protocol (LDAP) server is the user registry, then a distinguished name (DN) is sent.

6. Configure a trusted server list.
   When identity assertion is selected for inbound requests, insert a pipe-separated (|) list of server administrator IDs to which this server can support identity token submission. For backwards compatibility, you can still use a comma-delimited list. However, if the server ID is a distinguished name (DN), then you must use a pipe-delimited (|) list because a comma delimiter does not work. If you choose to support any server sending an identity token, you can enter an asterisk (*) in this field. This action is called presumed trust. In this case, use SSL client certificate authentication between servers to establish the trust.

   Supported configurations: This step applies if you are using a Lightweight Directory Access Protocol (LDAP) or custom user registry. However, it does not apply when you are using the local operating system user registry or a System Authorization Facility (SAF) user registry.
7. Configure session management.
   You can choose either stateful or stateless security. Performance is optimum when choosing stateful sessions. The first method request between a client and server is authenticated. All subsequent requests (or until the credential token expires) reuse the session information, including the credential. A client sends a context ID for subsequent requests. The context ID is scoped to the connection for uniqueness.