How to open a port on CentOS 6?

Question

CentOS

Hello.
On the Internet, they write that the ports are opened by the command

iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT

if after that check
iptables --line-numbers -n -L
the record appears

Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
1    ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:8080

Chain FORWARD (policy ACCEPT)
num  target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source               destination

but when scanning using the
nmap IP_адрес
port is not in the list

PORT   STATE SERVICE
22/tcp open  ssh

Tell me, please, what am I doing wrong?

Answer 1

What gives out?
netstat -an

Answer 2

And what service do you have hanging on port 8080 that you want to see it in the nmap list?