# Technical Requirements ## Hardware Each instructor requires access to a laptop computer with a front-facing camera and with the ability to disable the touchscreen during all instructional sessions. The laptop must be connected to the internet. We recommend that the computer has at minimum 4 GB RAM and Intel Core i3 processor or equivalent. There is no minimum storage requirement, since no files are stored on the computer as part of the Once program. ## Software/Networking Once is cloud-based and does not require any software to be downloaded or installed. The Once portal is available at [https://go.tryonce.com](http://go.tryonce.com/). This URL redirects to a page built on Google Firebase. If your network filters out Firebase or redirects more generally, you will need to make an exception for go.tryonce.com. You should also ensure that all `tryonce.com` subdomains are whitelisted, such as `api.tryonce.com`, `curriculum.tryonce.com`, and `docs.tryonce.com`. We add new subdomains from time to time, so the best approach is to whitelist `https://*.tryonce.com` The Once portal also utilizes the following services which should be whitelisted. 1. HTTPS connections to: 1. 2. 3. 4. [https://\*.explo.co/\*](https://*.data.explo.co/) 5. [https://\*.sentry.io/\*](https://us-east-1.data.explo.com/) 6. [https://\*.launchdarkly.com/\*](https://us-east-1.data.explo.com/) 7. [https://\*.amplitude.com/\*](https://us-east-1.data.explo.com/) 2. HTTPS connections converting to WebSockets on \*.[wss.daily.co](http://wss.daily.co/) 3. For best results, we recommend allowing traffic on \*.[daily.co](http://daily.co/). 4. must be reachable on TCP/443 5. prod-ks.pluot.blue must be reachable on TCP/443 6. \*.[stun.twilio.com](http://stun.twilio.com/) must be reachable on TCP/UDP/3478 or TCP/443 7. \*.[wss.daily.co](http://wss.daily.co/) should be reachable on TCP/443 and UDP/40000-65534 8. Additionally, your proxy server should handle these requirements if you're using one.