Need Info on Web Crawler IP Addresses

Is there any information available regarding the IP address of the crawlers used when crawling web pages with the “Crawl Web Domain” in the SaaS environment?

As background, the content I want to crawl exists within our internal network, so I need to set up access permissions through the firewall. I can assume that either TCP port 80 or 443 will be used, but without knowing the IP address, I cannot configure the firewall settings.