The Salesforce Marketing Cloud Account Engagement connector is a Palantir-provided driver connector. The official documentation for this driver can be found here ↗.
Networking
If using an agent connection, the agent must be allowed to connect to the system you choose. This means that the agent must be able to reach the destination IP address, and the destination system must be configured to allow connections from the agent.
If using a direct connection, be sure to add the following egress policies to the connector:
Domain
Required
<Subdomain>.soap.marketingcloudapis.com
Only if Schema=SOAP (default)
<Subdomain>.rest.marketingcloudapis.com
Only if Schema=REST
<Subdomain>.auth.marketingcloudapis.com
Only if UseLegacyAuthentication=FALSE (default) AND AuthScheme=OAuth, OAuthClient