Update 9 Dec 2020 10:15 am: ACOnet has deactivated its measures and reports that traffic levels have returned to normal.
Update 7:30 pm: At around 4:30 pm, we implemented a different mitigation strategy, which has up to now been successful at withstanding the attack. We are cautiously optimistic but continue to monitor the situation.
Update 1:00 pm: Unfortunately, the recent mitigation did not solve the issue. Please use the TU VPN if you encounter issues when accessing TUWEL.
Update 12:00 noon: TUWEL is now directly accessible from outside Austria again. Due to the caching behavior of DNS, it may still take a few hours until the new IP address of TUWEL is known worldwide. We still recommend using the TU VPN if you encounter issues with a direct connection.
Update 11:00 am: Due to the volume of the attack, ACOnet has implemented additional mitigation steps, which make TUWEL only partially accessible from outside Austria. We are in intense contact with the TSC to solve this limitation as soon as possible. For the time being, if you are having issues accessing TUWEL, please activate the TU VPN.
The attack is of the DNS amplification DDoS variety; its goal is to make a specific service unavailable – we assume that there will be no attempts to steal protected data.
ACOnet, TU Wien's Internet service provider, has already implemented mitigation techniques and we are monitoring the situation together. Thank you for your patience!