We block several outbound ports for network security. You may request these blocks be removed by [opening a support ticket](https://my.vultr.com/support/create_ticket/). * TCP port 25 (SMTP) * TCP & UDP port 137 (NetBIOS Name Service) * TCP & UDP port 138 (NetBIOS Datagram) * TCP & UDP port 139 (NetBIOS Session) * TCP & UDP port 445 (SMB over TCP) * TCP port 1688 (Microsoft [Key Management Server](https://docs.microsoft.com/en-us/windows-server/get-started/activation-troubleshoot-kms......