Arch Linux

Jakkin

Member

From: 403 Forbidden

Registered: 2014-10-16

Posts: 18

Closed ports on an open firewall w/ port forwarding enabled.

I'm running a closed network for my game development club and I need to be able to have each computer be able to communicate with each other for when the group tests out their new multiplayer games.
I decided to set up Arch as the operating system since they use Lenovo Thinkcentre M92p's right now. I also set up a seperate network server with Arch to take care of networking issues between the computers and because we aren't allowed to use the campus bandwidth.
The server has its own dhcp server running (dhcpd) and iptables set up to allow any and all connections. The computers have exactly the same iptables setup as well.
I've done basic scans of the computers using nmap and it always comes back with

Nmap scan report for localhost.localdomain (127.0.0.1)
Host is up (0.00033s latency).
All 1000 scanned ports on localhost.localdomain (127.0.0.1) are closed

If I try to scan the other computers, the report is no different. I've set iptables to accept incoming connections, wouldn't nmap say all ports are open?

Last edited by Jakkin (2014-11-04 03:09:56)

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Anyone who NEEDS to be TAUGHT how to interact with a computer probably shouldn't be allowed near one. -Sopwith

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,822

Re: Closed ports on an open firewall w/ port forwarding enabled.

What services are you running that you expect to open a port?  Just because a port is not blocked by the firewall, it does not mean that it is open.  You still have to run a service that listens on ports for them to be "Open"  DHCP servers don't open ports, so you won't see that service.

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Jakkin

Member

From: 403 Forbidden

Registered: 2014-10-16

Posts: 18

Re: Closed ports on an open firewall w/ port forwarding enabled.

I know dhcp servers don't open ports, mainly they just provide IP addresses to computers on the network.
I have ssh installed on all the computers (including the server), but the only computer that shows up on nmap is the server itself.
Its kinda embarrassing, but how I found out about the port problem was from testing the network using TF2. When I used my Netgear router as the dhcp server, TF2 worked perfectly. Since I've migrated to the new server and disabled dhcp on my router, TF2 hasn't worked. The computers can see each other, but, other then sshing into the server, they can't seem to connect to each other.

Last edited by Jakkin (2014-11-04 05:15:00)

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Anyone who NEEDS to be TAUGHT how to interact with a computer probably shouldn't be allowed near one. -Sopwith