Question All my ports are closed!

Oxicoi

Commendable
Feb 7, 2017
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Hello,

I have an ASUS RT-AC3100 that is IP-passthrough by an ATT router/modem. When port forwarding ANY ports, it won't open. I've tried to DMZ the ASUS router to the ATT one and STILL no luck.

I'm so confused and I really need help. I've been at it for 5 hours with no luck...

EDIT: Firewall is even turned off for both!
 

Ralston18

Titan
Moderator
How are the those two network devices and other network devices connected?

"ATT" being AT&T?

Which model AT&T modem/router?

Line diagram:

ATT (ISP) --->telephone line---> ATT modem/router --->Ethernet cable --->[WAN] ASUS RT-AC3100 [LAN] ---Ethernet cable --->PC with port(s) to be opened. Plus ~~~> wireless connections to wireless devices from the ASUS router.

Correct the line diagram as necessary.

For most networks the ATT modem/router will have DHCP disabled. The ASUS router will have DHCP enabled and handle all routing.

The PC being used will need to have a static IP address reserved for the PC on the ASUS router using the PC's MAC. The assigned static IP will need to outside of the allowed DHCP IP address range set up on the ASUS Router. No other device can have that assigned static IP.

Do you have the User Guides/Manual for both devices?

Who has full admin rights to both devices? That person will need to help you.
 

Oxicoi

Commendable
Feb 7, 2017
226
1
1,685
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How are the those two network devices and other network devices connected?

"ATT" being AT&T?

Which model AT&T modem/router?

Line diagram:

ATT (ISP) --->telephone line---> ATT modem/router --->Ethernet cable --->[WAN] ASUS RT-AC3100 [LAN] ---Ethernet cable --->PC with port(s) to be opened. Plus ~~~> wireless connections to wireless devices from the ASUS router.

Correct the line diagram as necessary.

For most networks the ATT modem/router will have DHCP disabled. The ASUS router will have DHCP enabled and handle all routing.

The PC being used will need to have a static IP address reserved for the PC on the ASUS router using the PC's MAC. The assigned static IP will need to outside of the allowed DHCP IP address range set up on the ASUS Router. No other device can have that assigned static IP.

Do you have the User Guides/Manual for both devices?

Who has full admin rights to both devices? That person will need to help you.
Diagram seems right. "ATT" is AT&T.

Everything was fine until today. It happened out of nowhere.

I want devices to connect to my ASUS router, not ATT. That's why I did passthrough using the ASUS MAC address. It is DHCP-fixed.

EDIT: I would like to POINT OUT HIGHLY that this worked yesterday and now everything doesn't. I've changed nothing since yesterday. All ports are either closed or blocked altogether, which I think they're blocked personally.

Even disabling the third party router (ASUS) doesn't fix the issue. I've even went on data on my phone to test a port and it's closed (even though that probably doesn't matter).

No ports are working and it is making no sense. Everything is correct, nothing is at error. Please know that.
 
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Ralston18

Titan
Moderator
Verify: The AT&T modem has its DHCP disabled - correct?

You have an Ethernet cable going from the AT&T modem (model number) to the ASUS Router.

What was that "ASUS MAC address" you used? What ports are being physically connected between modem and the router? Designed as WAN, LAN 1, LAN 2, etc....

Do you have the User Guides/Manuals for modem and router?

And what about admin rights?

Very little can be done to help with port forwarding without the necessary administrative access to both modem and router.

Especially if the problem happened out of nowhere.
 

Oxicoi

Commendable
Feb 7, 2017
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what are you trying to port forward? there is no practical way to test if all your ports are open. you would have to run a service on every port to see that.
An example port would be 25565

EDIT: The point I'm trying to make is that any port I port forward will not open. It doesn't matter entirely what the port is.
 
Last edited:
An example port would be 25565

EDIT: The point I'm trying to make is that any port I port forward will not open. It doesn't matter entirely what the port is.
If you port forward to any port that has no service running it won't do anything. a service has to be running to show "open" that is accepting TCP or UDP or which ever it's running on. run nmap on your LAN to see if a service is running on the port you are trying to forward to.
 

Oxicoi

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Feb 7, 2017
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If you port forward to any port that has no service running it won't do anything. a service has to be running to show "open" that is accepting TCP or UDP or which ever it's running on. run nmap on your LAN to see if a service is running on the port you are trying to forward to.
I did a port scanner and this is what I get (note that 25565 is port forwarded AND running):


Even if I were to open all of these, they will stay closed, not matter what I do. All these services are on 24/7 (I believe), so if it doesn't open even when forwarded, I have no clue what the issue is. My public IP allows for port forwarding or ports to be open (as it DID work before). I don't get why it all of a sudden stopped.

EDIT: I don't know what nmap is. I've tried doing DMZ so my AT&T router/modem can put ports on my ASUS router, but that doesn't work either, even if ports are forwarded on both ASUS and AT&T
 
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Oxicoi

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Feb 7, 2017
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After countless hours, only one port was able to get open: 80. I made my ASUS router an AP and my devices show up on my AT&T router. Even though ports I want are forwarded, they STILL will not open, yet 80 is open and is not forwarded.

Why is everything really difficult and not possible on my end? Example port would be 443, for HTTPS.
 
After countless hours, only one port was able to get open: 80. I made my ASUS router an AP and my devices show up on my AT&T router. Even though ports I want are forwarded, they STILL will not open, yet 80 is open and is not forwarded.

Why is everything really difficult and not possible on my end? Example port would be 443, for HTTPS.

if your AT&T modem is also a router why not just use it on its own? clearly this is an issue you are having because you are trying to run multiple routers.
 

Oxicoi

Commendable
Feb 7, 2017
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if your AT&T modem is also a router why not just use it on its own? clearly this is an issue you are having because you are trying to run multiple routers.
My ASUS router has QoS, which I love personally. I see major improvements when using it. AT&T just sucks as a whole with it's Windows XP look. It doesn't function properly. Not to mention it has to be put at a certain place in the house. I want Ethernet and if I'd have to connect directly to the AT&T router/modem, I'd literally have to buy a 125-150ft cable. I've been used to this ASUS router and it has had no problems until yesterday, without warning.

EDIT: Would like to say the ASUS router isn't the problem, even though it looks like I said that. Ever since using AP mode on the ASUS router, everything is super slow and has terrible spikes. I'm so clueless to this dumb issue...
 
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Oxicoi

Commendable
Feb 7, 2017
226
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1,685
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Verify: The AT&T modem has its DHCP disabled - correct?

You have an Ethernet cable going from the AT&T modem (model number) to the ASUS Router.

What was that "ASUS MAC address" you used? What ports are being physically connected between modem and the router? Designed as WAN, LAN 1, LAN 2, etc....

Do you have the User Guides/Manuals for modem and router?

And what about admin rights?

Very little can be done to help with port forwarding without the necessary administrative access to both modem and router.

Especially if the problem happened out of nowhere.
Disabling DHCP stops all connection

BGW210-700 ---E-cable--- ASUS RT-3100

ASUS MAC used is LAN, which is also the same as 2.4GHz MAC.

Ethernet is in E-port 1 of AT&T, other end is in the "Internet" port of ASUS

No full-length manuals/guides for either device

I'm able to change everything on each device

AT&T confirmed I have the privileges to port forward

EDIT: Is it possible to help me 1 on 1 like on Discord or something? Would be awesome.
 
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Ralston18

Titan
Moderator
My suggestion is to take a step back and reconsider everything .

First read some tutorials regarding port forwarding. For example:

https://www.lifewire.com/how-to-port-forward-4163829

https://www.noip.com/support/knowledgebase/general-port-forwarding-guide/

Be sure that you understand the overall concepts and what is required.

Second go online and look for the applicable User Guides/Manuals for your modem and router.

After reading the tutorials, the information and instructions in the User Guides should be much more understandable.

Verify that only one device is assigning DHCP IP addresses. Router recommended - not modem.

Ensure no duplicate IP addresses exist.

Third plan your port forwarding configuration. Sketch out a network diagram labeling all devices and drawing in the connections between devices. Keep the diagram simple but detailed enough that anyone looking at the diagram will have a sense of the overall network layout.

Be continually sure that everything else (your network, your internet connectivity) is working as expected. All DHCP IP addresses to begin with.

Then move on to assigning a static IP to the intended target computer and, once completed, again confirm that that computer is online.

Next, set up the desired/required ports via the router and the target computer's Static IP. Be sure to have that Static IP reserved for the target computer via the target computer's MAC.

Keep notes on the configuration settings: those already set, those you set or change. Avoid multiple changes at one time. If something goes astray it will be more difficult to identify the culprit.

And pay attention to the screens: You may need to "OK" , "Save changes" or "Apply". Those ending clicks are often overlooked when things get into a rush.
 

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