This exact question has been asked over the years, but I do not see a definitive answer.
Is a license required to get SouceTree to operate properly behind a firewall on a closed network?
Hi @Greg Rasche , welcome to the Community!
If you've got Bitbucket Server or Bitbucket Data Center behind your firewall as well as the machines that won't be able to connect to the internet, you can use the on-premise Bitbucket as a registration option for Sourcetree. Please see Sourcetree Enterprise and MSI Installation for a link to the MSI installer and details on how to use on-prem registration.