You need to be able to access the Internet from the isolated Virtual Lab.
NOTE: The function documented in this KB enables the virtual lab proxy appliance to act as an internet proxy. This proxy function only passes web browser traffic. This will not allow for any other type of traffic (e.g. ICMP, FTP, or SSH) to leave the isolated environment.
Within the configuration of the Virtual Lab, on the Proxy tab, select the Allow proxy appliance to act as internet proxy for virtual machines in this lab check box. In the Port field, specify a port for HTTP traffic. By default, port 8080 is used. In the Production proxy field, you can optionally specify an IP address or a fully qualified domain name of an Internet-facing proxy server that VMs must use to access the Internet.
After a VM has been started using this Virtual Lab you must adjust the proxy settings to enable internet access.
On Windows OS
To do this, open Internet Options > Connections > LAN Settings > Proxy server and specify the IP address of the proxy appliance on the isolated network and port number.
On Linux OS
Add http_proxy environment variable with export command: