http://protonmailrmez3lotccipshtkleegetolb73fuirgj7r4o4vfu7ozyd.onion/blog/protonmail-ddos-attacks
We would also like to thank Level 3 Communications for arranging an emergency IP Transit, and Patrick Muller, Pim van Pelt, David Corriveau, Ivan Adji-Krstev, and Michel Streiff for their assistance. In order to mitigate the DDoS attack against us, we partnered with Radware, one of the world’s premier DDoS protection companies.