Host-based security protection

Some environments require a host-based security system (HBSS) on the servers that run Kasm Workspaces. Products such as HBSS control iptables, which can cause confusion, because Docker and firewalld also control iptables. Confirm that your host-based security product allows TCP port 2375 and the port Kasm is configured to listen on.

In practice, iptables can occasionally enter a bad state when HBSS, firewalld, and Docker all modify it. Symptoms include containers that cannot communicate outbound or receive inbound traffic. Clearing all iptables rules and restarting Docker usually resolves these issues. When Docker restarts, it reconstructs all iptables rules for Docker and the containers it manages. Restarting firewalld may be required to rebuild the rules that firewalld manages. Consult your HBSS documentation for product-specific guidance.