If your organization passes data through a firewall, you need to configure the firewall to allow access to Salesforce.
If you cannot connect to Salesforce servers and receive a connection error, contact your network administrator to allow access to Salesforce servers.
For more information, see the following Knowledge Base article: Firewall rules
Note: IP addresses for Salesforce servers might change. For the latest information about the server IP addresses of Salesforce, see the Salesforce documentation.