The main question: Can Linux be used?
As everyone else has said, there should be no technical reason that Linux cannot access your school’s Internet connection.
For more specific information, I did a web search for “edustar internet”. The first result was an eduSTAR page on the Victorian government’s website, which says:
The eduSTAR platform provides schools with:
- A range of ICT services, which includes some of the following:
- eduSTAR.ISP — Department’s internet service provider (ISP) and internet security systems and reporting
This is not particularly useful, but at least it has contact details, which I intend to use if no clear answer is provided here.
The second result was a Victorian school support article about eduSTAR. Unfortunately, this article is not accessible via HTTPS, so I used the version archived in the Wayback Machine. It suggests that Android should work, as long as it can use a proxy. If Android works, then distributions commonly referred to as “Linux”, like Ubuntu, should also work.
The only other information I could find was that at least one Victorian school specifically prohibits Linux (and everything else, besides Windows and macOS) and requires devices to be inspected before being granted network access.
What can you do about it?
Get informed. Check your school’s documentation for connecting to the Internet (you said they don’t have any) and rules for devices generally (do they say anything about Linux?).
Also, you should not have to give any reason at all for using Linux. But if you do give a reason, give a proper reason. Like SnakeDoc’s comment says, the argument about Visual Studio is false and makes it look like you do not know what you are talking about. That is not good when you are accusing them of not knowing what they are talking about.
With all the information available, you can choose from the following options:
- Bypass the rule. There are two ways to do this:
- Connect directly using Linux. You may do this by copying the settings from Windows. This is probably a bad option, because it would annoy the school. If you are not in a position to change schools, you probably do not want to annoy the current school.
- Run Linux inside a virtual machine. For this method, you should ensure that Linux has only indirect (NAT) Internet access. This way, from the network’s point of view, Linux is not really an operating system; it is effectively just another normal program. This should be fine, provided you are allowed to install your own software, which it sounds like you are. (This is basically what rackandboneman’s answer says, but I started writing my answer much earlier.)
- Challenge the rule. You may do this by asking why it matters which operating system you use at all, by pointing out that Linux is safe and should connect just fine, and by pointing out that it is unfair to force students to purchase powerful hardware and licences for proprietary operating systems. But this is probably a bad option, because it would also annoy the school, unless you can get enough support from more powerful people.
- Comply with the rule. You may do this by running Windows at school (and using it only for school business) and Linux away from school. This is probably the best option, provided you are allowed to dual boot.
- Change schools. But you have already stated that you cannot do this.