Opening port with IP tables and UFW doesn't appear to open port

Question

I have attempted to open port 443 on a server I'm working on (Ubuntu 16.04):

/sbin/iptables -I INPUT -p tcp --dport 433 -m state --state NEW,ESTABLISHED -j ACCEPT

The port doesn't appear to be open:

nmap cubicverse.com

Starting Nmap 7.01 ( https://nmap.org ) at 2017-06-18 17:52 BST
Nmap scan report for cubicverse.com (104.131.17.139)
Host is up (0.15s latency).
Not shown: 998 closed ports
PORT   STATE SERVICE
22/tcp open  ssh
80/tcp open  http

Nmap done: 1 IP address (1 host up) scanned in 39.61 seconds Product of iptables -L:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:433 state NEW,ESTABLISHED

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

I have also opened the port with ufw.

What alternative steps may be needed to open the port?

I am attempting to add an SSL cert for this server, and the 'SSL checker' keeps telling me I have a closed port and hence it can't validate the CSR.

I also know the port isn't open because:

decoder.link/sslchecker/www.cubicverse.com/443

Solution

To open port with iptables command is

sudo iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT

For UFW

sudo ufw allow 443

Experience has learn me that it not good to mix iptables and ufw. Use only one of them.

Comments

[steeldriver]

Is this any more than a simple typo? you've opened 433 whereas the checker appears to require 443

[Peter David Carter]

@Thomas no-one would have answered there. If there is a referencing criteria please tell me.

[Peter David Carter]

@steeldriver upvoted