Virtual server / port forwarding / DMZ is not working at all

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Virtual server / port forwarding / DMZ is not working at all

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Virtual server / port forwarding / DMZ is not working at all
Virtual server / port forwarding / DMZ is not working at all
2022-02-04 07:44:07 - last edited 2022-02-08 01:02:52
Model: Archer VR400  
Hardware Version: V3
Firmware Version: 1.3.0 0.9.1 v00a1.0 Build 201109 Rel.54507n

Hello community,

 

 

I'd bought an Archer VR400 v3 yesterday, and trying to expose a port on my local machine to the internet, but it never worked; here is summary of my situation:

 

 - My local machine is listening on port 4000

 - It is accessible from other nodes in the local network.

 - I'd setup virtual server on tp-link modem to listen 4000:4000 IP my local machine 

 

Now I expect 192.168.1.1:4000 to be open and responds from local machine, but it is not; the only thing I get is connection refused. 

the packet doesn't even reach the local machine, modem doesn't allow and drop connection.

 

I'd tried to setup on different ports, even changed local management port on modem from 80 to other ports, and tried to use port 80 for my own use-case but then port 80 becomes "connection refused". I tried DMZ that local machine, didn't work; tried port forwarding, didn't work; 

 

The problem is any port other than the tp-link local management console is blocked, modem drops the connection, no matter what. I'd tried turning off the SPI firewall, and it didn't change anything as well.

 

 

I have IP static and my modem can be viewed remotely, so if it helps, DM me to give you the credentials to see it for yourself

 

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#1
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1 Accepted Solution
Re:Virtual server / port forwarding / DMZ is not working at all-Solution
2022-02-06 15:59:13 - last edited 2022-02-08 01:02:52

@Leonardo_ala 

 

When you're addressing http://192.168.1.1:4000 you're expecting that your VR400 has a service running on port TCP 4000 - which I suppose it doesn't.

If the service in question is running on 192.168.1.33, when accessing from your local network you should use http://192.168.1.33:4000.

While if you're trying to access that service from outside your local network (external network) then you should use http://<your_public_IP_address>:4000

Does http://<your_public_IP_address>:4000 work when you try to access from an external network ?

 

 

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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-04 14:34:41 - last edited 2022-02-08 01:02:52

@Leonardo_ala 

 

Make sure that your Internet IP address is public:

 

The LAN IP address of your local machine shouldn't be 192.168.1.1 (since that's probably the LAN IP address of your VR400).

You need to set the correct LAN IP address of your local machine in the VR400 Virtual Servers (for example if it's 192.168.1.100):

 

 

Also set the correct Protocol type - TCP, UDP or ALL.

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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-06 07:06:53 - last edited 2022-02-08 01:02:52

Thanks you for follow up dear @terziyski 

 

 

My Ip is public, you can even view my router here (http://91.92.206.172:65535/), but the the problem I stated was that 

the virtual server port on modem WAS NOT accessible even from local network; for instance -> 192.168.1.1:4000 

if the modem doesn't respond the local port, certainly it wouldn't be accessible from internet.

 

 

The ports exposed here ( e.g. 192.168.1.33:54321 ) are accessible from other local machines

 

 

Do you have any idea how can I debug this?

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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-06 15:29:45 - last edited 2022-02-08 01:02:52

@Leonardo_ala 

 

What about 192.168.1.33:4000 ? Is this the device (192.168.1.33) that's running the service in question on its port 4000 ?

You should be able to access that from your local network.

According to the virtual server configured if there's a active service at TCP port 4000 on 192.168.1.33 device, you should be able to access it from external network like this:

http://91.92.206.172:4000 if it is a HTTP server.

The other thing you should check is if your public Internet IP address is static or dynamic.

If it is dynamic then on every device reboot or internet session restart you'll receive a different public IP address.

If that's the case you should use the Dynamic DNS feature to register an account (if no-ip.com for example) and use this <your_domain>.no-ip.com for accessing your router from an external network:

 

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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-06 15:42:56 - last edited 2022-02-08 01:02:52

@terziyski 

 

My IP is a permanent static IP, no problem on that side; and my server at 192.168.1.33 is listening on 4000, 54321 and 80 ports. ( it's a simple http server ), 

I can call it from my machine ( 192.168.1.100 ), but I don't get anything from modem at all.

 

I think this piece of code worth more than a thousand words:

 

 

Refused to connect : (

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#5
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Re:Virtual server / port forwarding / DMZ is not working at all-Solution
2022-02-06 15:59:13 - last edited 2022-02-08 01:02:52

@Leonardo_ala 

 

When you're addressing http://192.168.1.1:4000 you're expecting that your VR400 has a service running on port TCP 4000 - which I suppose it doesn't.

If the service in question is running on 192.168.1.33, when accessing from your local network you should use http://192.168.1.33:4000.

While if you're trying to access that service from outside your local network (external network) then you should use http://<your_public_IP_address>:4000

Does http://<your_public_IP_address>:4000 work when you try to access from an external network ?

 

 

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Recommended Solution
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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-06 17:34:12 - last edited 2022-02-08 01:02:52

@terziyski 

 

 

Hmmm, you were right.

 

192.168.1.1:4000 doesn't work, and probably shouldn't as well,

but when I put check <PUBLIC_IP>:4000 from another external network (e.g. mobile LTE ) it works!

 

the virtual server works as expected from external network and my issue is fixed and closed at this point.

thank you for the follow up 🙏🏼

 

 

Btw for the sake of curiosity, I would like to ask you why I get "connection timed out" when I try 

91.92.206.172:4000 from a node inside the internal network?

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#7
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Re:Virtual server / port forwarding / DMZ is not working at all
2022-02-06 20:38:12 - last edited 2022-02-08 01:02:52

@Leonardo_ala 

 

Here's some brief explanation on how NAT (in particular port-forwarding) works, just FYI.

Your last question is related to so called NAT loopback (hairpinning) - if it's implemented on your device it should work.

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