I installed on a german V-Server Frappe and ERPNext in a multi tenant setup. I used following install routine:
All ERPNext subdomains are with ssl secured via Let’s Encrypt.
All subdomains are registered at my domain provider and the dns a-record is set to the IP of my virtual ubuntu 18.04 cloud server.
With this server running i’ve got an email from our german state department of information security. They said i have an “open dns resolver” running. It is just a hint from them because this can be used for DDoS-Reflection/Amplification-attacks and they advice to convert that “open dns resolver” by disable recursion or limit recursion to trusted clients in the DNS server’s configuration.
How can i solve this problem with my current setup?
Thanks for your advice