Is Firewall for Dash Masternode even needed ?

[Technologov]

The only difference (as far as I know) between Firewalled Masternode and Non-Firewalled MN, is that the Linux kernel will DROP packets in FW case or simply send REJECT ICMP message for non-FW Nodes.

In both cases I have only 2 ports OPEN: TCP/22 (SSH) and TCP/9999 (Dash).

 

[Newar]

There is more to it with regards to DDOS etc.:

[...]
Meanwhile, you can mitigate the attack by following steps in iptables setup part of this guide https://www.dash.org/forum/threads/how-to-set-up-ec2-t1-micro-ubuntu-for-masternode-part-2-3.241/

 

[solo7861]

I highly recommend either having ufw or iptables running and have something like DDOS mitigating in front of it.
I would also change your ssh port from say 22 to another port number
and would look at enableing 2fa on your cloud server:

2fa : https://www.vultr.com/docs/how-to-s...sh-on-ubuntu-14-04-using-google-authenticator
changing ssh port: https://uk.godaddy.com/help/changing-the-ssh-port-for-your-linux-server-7306
iptables rules: https://gist.github.com/chaeplin/5dabcef736f599f3bc64bdce7b62b817 - these inlcude rate limiting

Enjoy!