Port forwarding Issue

[JimT]

System Information from OpenWRT: Status > Overview:
|Model|ZBT-WE826 (16M)|
|Architecture|MediaTek MT7620A ver:2 eco:6|
|Firmware Version|OpenWrt SNAPSHOT r9614-b61495409b / LuCI Master (git-19.065.57576-61ea3ed)|
|Kernel Version|4.14.105|

Issue: I am not able to access a web page hosted on a windows PC from outside my private network.

In OpenWRT I have set port forwarding under Network > Firewall > Port Forwards to point to the PC's dynamically assigned IP address and the required port.

My public IP address (at the cell modem) is fixed and I can ping this IP address from outside my network (e.g. from a cell phone) but I cannot connect get access to my hosted web page.

I have tried disabling the firewall but still no success (disable SYN-flood protection).

I would appreciate your input. Thanks.

[eduperez]

Is the firewall in the Windows PC configured to accept incoming connections from any pubic IP address?

[JimT]

I checked and yes I have it set to allow remote connections to the computer.

[psherman]

@JimT

My public IP address (at the cell modem) is fixed and I can ping this IP address from outside my network (e.g. from a cell phone)

Many cellular providers do not give you a publicly routable IP address (although it is certainly possible yours does). Take a look at the WAN address on your OpenWrt router and compare that against the reported IP address when you do an external IP check (such as googling "what's my IP" or any other service). If they match, that's great. If not, you might have CG-NAT and you won't be able to reach it from the internet.

[JimT]

One thing curious to me is that in the OpenWRT administrator under Network > modem > network connection > IPv4 configuration > IP Address: it list a private IP (10.7.127.174) rather than the public IP provided by AT&T, is this normal?

[psherman]

@JimT

it list a private IP (10.7.127.174) rather than the public IP provided by AT&T, is this normal?

Yes, AT&T is providing a NAT service because IPv4 addresses are in short supply.

Because of this NAT, you do not have a public IP address and you will not be able to reach your system from the internet.

[JimT]

@psherman

WAN address on your OpenWrt router

Maybe this is the issue but in OpenWRT I'm not able to find specifically listed WAN Address, I can only locate the IPv4 address: 10.7.127.174.

[JimT]

but I am able to ping the public IP address?

[psherman]

@JimT

I can only locate the IPv4 address: 10.7.127.174.

If this is the “IPv4 Upstream” address, it is tour WAN

[psherman]

@JimT

but I am able to ping the public IP address?

Yes, but you can (almost) always ping the public IP address. But your router doesn’t actually have a public up address assigned. It has an RFC1918 private network assignment behind a NAT router at AT&T. The NAT router has a public IP address (likely a pool of them) to interface with the internet.

[JimT]

Thank you for your help it may have saved days of effort. One last question, are there any other options to allow my PC serve a web page from the internet using my current AT&T service?

[JimT]

It's odd that we paid AT&T extra for a fixed IP and assumed it is primarily for the purpose of hosting or accessing the hardware behind the router.

[slh]

If you're very lucky, you may be able to get an IPv6 address from your cell phone service - details depend on your ISP in question (sorry, different continent, no experience with AT&T - and even then the ISP might do rigorous filtering).