IPtables dynmap

I ran into this problem a couple of days ago and I can’t find a way to fix it. I want to open the default dynmap port (8123) but I can’t open it!
The commands, I did:

iptables -A INPUT -p tcp -m tcp --dport 8123 -j ACCEPT
iptables-save > /etc/iptables-rules
iptables-restore < /etc/iptables-rules

Thanks in advance!

Before you save rules, you should test them. Your first command should take effect immediately. So, after you type in that command, type in iptables --list. Do you see your new item there?

I did that and I see that item…
This is my list (a part of it):
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT tcp – anywhere anywhere tcp dpt:8123

So it seems like it’s open then. What’s the error behavior you’re seeing?

I don’t see any error! It’s just closed… What can it be?

How do you know it’s closed? From all appearances, the firewall isn’t the issue. Are you sure Dynmap isn’t the issue?

I’m totally not sure that my firewall is the issue :P.
I checked it with http://www.yougetsignal.com/tools/open-ports/. It says it’s closed.
IP: play.dreamworld.cf Port: 8123
What can the problem be?

I’m currently reinstalling dynmap, so I am sure that that isn’t the problem.

You can try literally any port and it will also say ‘closed’. Closed means ‘nothing is listening’. So if you tested port 3333, it’d also say ‘closed’ whether or not you fiddle with the firewall.

If you need further assurance, turn off the firewall.

iptables -P INPUT ACCEPT
iptables -F

If it still says ‘closed’, you know it’s not the firewall, it’s dynmap.

When I do that, any cracked client will be able to join my server…
What can the problem with dynmap be?

I think you’re misunderstanding what a firewall does…it has absolutely nothing to do with allowing cracked clients.

It will allow the access to my back-end servers for other players. They are in offline-mode for my bungeecord.

When I try to start a minecraft server on port 8123, it says "Failed to bind port. Perhaps it’s already in use. ". Is that normal?

Why are you trying to start a minecraft server on your dynmap port?

@hexparrot To try accessing it. When I am able to connect to it, the firewall will be open.

Disabling the firewall will do the exact same thing and has no impact on which clients can connect.

And it has the benefit of not trying to have a Minecraft server and a dynmap server open on the same port.

I know but that was my alternative… I got my information here: https://www.spigotmc.org/wiki/firewall-guide/

I’m trying to create a server on the 8124 port to test that port. When I enable it, I can’t access it. I opened the firewall up too in this case.

Hi @Christophe6.
Opening a port in a firewall is not equal of that being open (even though we are saying "Opening the port). It is merely you telling the operating system that you will allow connections through that port. You still need something listening on that port for it to actually be open.

After opening the port, did you actually start a service listening on it as well? Is the server you configured to use that port, or dynmap, running?

Are your MineOS machine connected directly to the internet? Or is it connected to your LAN? Are you trying to connect with a local client on the same LAN that your server runs on?

If the server is placed on a LAN (with IP 10...* or IP 192.168.* *), and you are trying to connect from the internet you also need to configure port forwarding. The firewall in MineOS is not the only one, you have one in your Internet router as well.

As for your server connected through bungeecord, here’s a tip:
Since Bungee (as far as I know) relays connections, you can configure your other servers to allow connections from only Bungeecord. At leas if those servers are running on the same MineOS-installation. Just set them to only listen to (localhost). This would allow bungeecord, and its connections through, but not anyone trying to connect directly.

I do this with my Dragonet - Minecraft connection when I test if they have released a working version yet. (Dragonet is a Minecraft Pocket Edition to Minecraft PC server bridge, working in prettty much the same way as bungeecord). My listening minecraft PC server is set to only accept connections from, and Dragonet is set to pass on connections to the local server. Since they communicate on the same server, all they need to talk is the localhost adress. Anyone else trying to connect will be ignored. (I do this because my some of my users are to young to have a xbox or Minecraft account, and only uses Minecraft Pocket Edition for iPad, and thus cannot log in on any other server than a “offline” server)

That’s it! I forgot to portforward although I’m with a VPS host… How can I portforward there.
And why isn’t it possible to start a minecraft server on the for now not used dynmap port?