It depends how Mandrake 10.1 was installed, it could load some services that are required by your environment. E.g FTP, NFS ..... As such, unused services should be stop or removed from the system. Used the nmap tool to scan for ports services open and then stop those services.

With the firewall (iptables) enable on server to accept on IP address from trusted network thus prevent hacker from using Mandrake system to hack the trusted network.

Default Mandrake 10.1 kernel not secure, but then your server is on a trusted network so not need to patch the kernel.