A landmark ruling on piracy and privacy on the internet means thousands of Australians could be getting letters threatening legally action if they illegally downloaded and shared Hollywood film Dallas Buyers Club. But internet law experts say the company behind the letters will have a hard time following through on the threats because it is very difficult to prove who is legally responsible for the downloading. The Federal Court ruled on Tuesday that Australian internet companies, including iiNet and other ISPs, should hand over the names and residential addresses of 4,726 people who illegally shared the film. Scroll down for video . Internet companies will have to reveal names, IP addresses and residential addresses of 4,726 people who uploaded the film The Dallas Buyers Club online illegally . Internet companies iiNet Limited, Internode, Amnet Broadband, Dodo Services, Adam Internet and Wideband Networks were all affected by the ruling . But legals experts say even if you are hit with a legal threat there are several ways to defend the accusations, Fairfax Media reports. iiNet's former chief regulatory officer, Steve Dalby, said the letter was not proof and it would be difficult for the film's studio to prove someone downloaded it. He said those hit with legal letters should also consider whether anyone else may have had access to their network. 'They can't detect downloaders so if I downloaded it but never shared it I wouldn't be concerned about it,' Mr Dalby said. 'If they're not guilty and had an open access point that was unsecured or were very free to giving their password out to people then maybe they do have the defence that it wasn't them. 'Most of the agreements state the account holder is responsible for the use of the account but there's no formal, legal obligation for customers to secure their WiFi.' He said if a letter did show up, it was important to seek legal advice. Slaters Intellectual Property Lawyers' Anny Slater told Fairfax Media there were many avenues for people to get advice. 'As to people getting access to justice and support, this case has brought to light the situation so there are many avenues for people to get advice on a cost effective basis,' she said. 'Some might argue innocence, some might argue that they didn't understand the repercussions, some might argue that the only access to the material was this way because prices were so high.' iiNet has warned its customers to expect speculative invoicing - an 'intimidating' letter demanding significant sums of up to US$7000 for an alleged infringement, or threatening court action . The owner of the copyright to Dallas Buyers Club - starring Matthew McConnaughey - have won their court battle . The court ruling handed down by Justice Nye Perram on Tuesday ordered that the identity of those who shared the content online using peer-to-peer sharing network Bit Torrent would be provided to the film's Hollywood studio, Dallas Buyers Club LLC. This includes their names, IP addresses and residential addresses. Internet companies iiNet Limited, Internode, Amnet Broadband, Dodo Services, Adam Internet and Wideband Networks were all affected by the ruling. The ruling means the Hollywood studio can now go after each individual to claim compensation. Justice Perram did not signify any limit to the amount of damages that the copyright holder of the film could claim directly from each individual. 'It is not beyond the realm of possibilities that damages of a sufficient size might be awarded under this provision in an appropriately serious case in a bid to deter people from the file sharing of films,' Justice Perram said. Justice Nye Perram did not signify any limit to the amount of damages that the copyright holder of the film could claim . iiNet has warned its customers to expect speculative invoicing - an 'intimidating' letter demanding significant sums of up to US$7,000 for an alleged infringement, or threatening higher costing court action. However, Mr Perram said in his ruling: 'I will also impose a condition on the applicants that they are to submit to me a draft of any letter they propose to send to account holders associated with the IP addresses which have been identified. The applicants will pay the costs of the proceedings'. He added that this: 'will prevent speculative invoicing'. In his ruling, Justice Perram said the details of each individual had to be kept private by the studio. Marque Lawyers boasted of their win in the courtroom on Tuesday over Twitter, writing: 'Dallas Buyers Club - we won. iiNet required to hand over ID of copyright infringements to the film studio. It's a big precedent…' 'What does Dallas v iiNet mean for unauthorised uploaders? It means you should probably stop doing that.' The internet service providers are yet to reveal whether they plan to appeal the ruling in the designated 28 days. Marque Lawyers boasted of their win in the courtroom on Tuesday over Twitter .
Companies will have to reveal names, IP addresses and residential addresses of 4,726 people who uploaded the film online illegally . This will allow the film's copyright holders to seek damages or court action . Internet provider iiNet warned they could demand up to $7000 . Justice Nye Perram ruled that individuals' privacy must be kept and all letters from the copyright holder must be sent to him first .