Options for configuring TLS

This page applies to Apigee and Apigee hybrid.

View Apigee Edge documentation.

This section shows how to configure TLS for traffic from a proxy to a target.

About setting TLS options in a target endpoint or target server

A target can be represented by an XML object like the one below:

<HTTPTargetConnection>
    <Properties/>
    <URL>https:myTargetAddress</URL>
    <SSLInfo>
        <Enabled>true</Enabled>
        <Enforce>true</Enforce>
        <ClientAuthEnabled>true</ClientAuthEnabled>
        <KeyStore>ref://myKeystoreRef</KeyStore>
        <KeyAlias>myKeyAlias</KeyAlias>
        <TrustStore>ref://myTruststoreRef</TrustStore>
        <IgnoreValidationErrors>false</IgnoreValidationErrors>
        <Protocols>myProtocols</Protocols>
        <Ciphers>myCipher</Ciphers>
    </SSLInfo>
</HTTPTargetConnection>

The area of the target endpoint configuration that you modify to configure TLS is defined by the <SSLInfo> tag. You use the same <SSLInfo> tag to configure a target endpoint or target server.

For information about the child elements of <SSLInfo>, see TLS/SSL TargetEndpoint configuration.

The following table describes the TLS configuration elements used by the <SSLInfo> tag:

Element	Description
<Enabled>	The <SSLInfo> block can be used for both one-way and two-way TLS/SSL. If set to true, <Enabled> specifies that the <SSLInfo> block should be used. When set to false, the <SSLInfo> block is ignored. The default value of <Enabled> is true if <URL> specifies the HTTPS protocol, and false if <URL> specifies HTTP.
<Enforce>	Enforces strict SSL between Apigee and the target backend. If set to true, connections will fail for targets with invalid certs, expired certs, self-signed certs, certs with a hostname mismatch, and certs with an untrusted root. A failure code of 4xx or 5xx is returned. If unset, or set to false, the result of connections to target backends with problematic certs depends upon the setting of <IgnoreValidationErrors> (see below). A success response (2xx) can occur under certain conditions, if <IgnoreValidationErrors> is set to true.
<ClientAuthEnabled>	Enables two-way TLS (also known as mutual TLS or mTLS) between Apigee and the API client, or between Apigee and the target backend. Enabling two-way TLS typically requires that you set up a truststore on Apigee and a truststore.
<KeyStore>	A keystore containing private keys used for outbound client authentication
<KeyAlias>	The alias specified when you uploaded a cert and private key to the keystore.
<TrustStore>	A keystore containing trusted server certificates.
<IgnoreValidationErrors>	Indicates whether validation errors are ignored. If the backend system uses SNI and returns a cert with a subject Distinguished Name (DN) that does not match the hostname, there is no way to ignore the error and the connection fails. Note: If <Enforce> is set to true, the value of <IgnoreValidationErrors> is ignored.
<Ciphers>	Supported ciphers for outbound TLS/SSL. If no ciphers are specified, then all ciphers available for the JVM will be permitted. To restrict ciphers, add the following elements listing the supported ciphers: <Ciphers> <Cipher>TLS_RSA_WITH_3DES_EDE_CBC_SHA</Cipher> <Cipher>TLS_RSA_WITH_DES_CBC_SHA</Cipher> </Ciphers>
<Protocols>	Supported protocols for outbound TLS/SSL. If no protocols are specified, then all protocols available for the JVM will be permitted. To restrict protocols, specify them explicitly. For example, to allow only TLS v1.2 or TLS v1.3: <Protocols> <Protocol>TLSv1.2</Protocol> <Protocol>TLSv1.3</Protocol> </Protocols>

About setting the <KeyStore> and <TrustStore> elements

In the example above, the keystore and truststore are specified by using references, in the form:

<KeyStore>ref://myKeystoreRef</KeyStore>
<TrustStore>ref://myTruststoreRef</TrustStore>

Apigee strongly recommends that you always use references to the keystore and truststore. A reference is a variable that contains the name of the keystore or truststore, rather than specifying the keystore name directly. In this example:

• myKeystoreRef is a reference that contains the name of the keystore. In this example, the name of the keystore is myKeystore.
• myTruststoreRef is a reference that contains the name of the truststore. In this example, the name of the truststore is myTruststore.

When a cert expires, you have to update the target endpoint/target server to specify the keystore or truststore containing the new cert. The advantage of a reference is that you can modify the value of the reference to change the keystore or truststore without having to modify the target endpoint/target server itself:

Changing the value of the reference does not require you to contact Google Cloud Customer Care.

Alternatively, you can specify the keystore name and truststore name directly:

<KeyStore>myKeystore</KeyStore>
<TrustStore>myTruststore</TrustStore> 

If you directly specify the name of the keystore or truststore, then you must contact Google Cloud Customer Care.

A third option is to use flow variables:

<KeyStore>{ssl.keystore}</KeyStore>
<TrustStore>{ssl.truststore}</TrustStore> 

Flow variables work let you update the keystore or truststore like references. For more information, see Using flow variables to set TLS/SSL values dynamically.

About configuring TLS

All Apigee customers, both paid and evaluation, have complete control over the configuration of target endpoints/target servers. In addition, paid Apigee customers have complete control over TLS properties.

Handling expired certificates

If a TLS certificate expires, or if your system configuration changes such that the certificate is no longer valid, then you need to update the certificate. When configuring TLS for a target endpoint/target server, you should decide how you are going to perform that update before you perform any configuration.

Note: You cannot update an existing keystore or truststore to add a new certificate. You must create a new keystore/truststore when updating a certificate. Typically, you create the new keystore/truststore and upload the new cert before the cert in the old keystore/truststore expires. This lets you test the new keystore/truststore and rollback to the old keystore/truststore if there are any issues.

When a cert expires

On Apigee, you store certs in one of two places:

• Keystore - Contains the TLS certificate and private key used to identify the entity during TLS handshaking.
• Truststore - Contains trusted certificates on a TLS client used to validate a TLS server's certificate presented to the client. These certificates are typically self-signed certificates, certificates signed by a trusted CA, or certs used as part of two-way TLS (also known as mutual TLS or mTLS).

When a cert in a keystore expires, and you are using a reference to the keystore, you cannot upload a new cert to the keystore. Instead, you:

1. Create a new keystore.
2. Upload the new cert to the new keystore using the same alias name as in the old keystore.
3. Update the reference in the target server/target endpoint to use the new keystore.

When a cert in a truststore expires, and you are using a reference to the truststore, you:

1. Create a new truststore.
2. Upload the new cert to the new truststore. The alias name does not matter for truststores. Note: If a cert is part of a chain, then you must either create a single file containing all the certs and upload that file to a single alias, or upload all certs in the chain separately to the truststore using a different alias for each cert.
3. Update the reference in your target server/target endpoint to use the new truststore.

Summary of methods for updating an expired cert

The method that you use to specify the name of the keystore and truststore in the target endpoint/target server determines how you perform the cert update. You can use:

• References
• Direct names
• Flow variables

Each of these methods has different repercussions on the update process, as described in the following table:

Config type	How to update/replace cert	Usage
Reference (Recommended)	For a keystore, create a new keystore with a new name and an alias with the same name as the old alias. For a truststore, create a truststore with a new name.	Update the reference to the keystore or truststore. No need to contact Apigee Support.
Flow variable	For a keystore, create a new keystore with a new name and an alias with the same name or with a new name. For a truststore, create a truststore with a new name.	Pass the updated flow variable on each request with the name of the new keystore, alias, or truststore. No need to contact Apigee Support.
Direct	Create a new keystore, alias, and truststore.	Redeploy the proxy.
Direct	Delete the keystore or truststore and recreate it with the same name.	API requests will fail until the new keystore and alias are set. If the keystore is used for two-way TLS (also known as mutual TLS or mTLS) between Apigee and the backend service, contact Google Cloud Customer Care to restart the Message Processors.
Direct	For truststore only, upload a new cert to the truststore.	Contact Google Cloud Customer Care to restart the Message Processors.