Cudy AC1200 Cellular Modem/Router with WiFi

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Hello.  I purchased this Cudy AC1200 Router/Modem and got an Internet-only prepaid plan with TM. However, I can’t do services that can be had with a normal Internet connection from cable or DSL! The Modem/Router is capable of setting up DDNS, an L2TP VPN server, etc., but none of that is working!  The DDNS complains because the outside IP address is a “Private” IP.  The L2TP is NOT reachable.  I had set the Modem/Router to respond to ping from WAN but when I ping the “Public” IP addresss that is shown on the Modem/Router status, it does not respond to ping!

 

Why is there two IP addresses shown on the Cellular status field? Example: the Public is 172.58.207.82 then there is an “IP Address” of 172.32.84.244.  AND when I check my IP Address from a whatismyipaddress.com, it gives me 172.58.207.41!!!  Why is that???

 

I was going to use this to replace a cable internet service to my townhouse that I’m going to put in the market.  The cable internet is going to be moved to my son’s apartment so I need to have access to my network in the townhouse (cameras, garage door, thermostat) while it is on the market. With these issues, I can’t access my LAN from remote!

 

Cellular home internet is totally a different animal!

 

Is there a way to having a straight-forward Internet connection using TM?  Thanks in advance.

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iTinkeralot
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You have made the correct observation, “Cellular home internet is totally a different animal!”

Even if you setup the T-Mobile home internet gateway you would possibly find your communication with the cameras, garage door, thermostat etc… are yet another challenge in some cases. Due to the way T-Mobile uses CGNAT and the firewall rules you will not be able to do port forwarding to get access remote. There is another solution but it is more cost and well technical effort so might also not be a solution you want to get into. 

You might be better off using the existing solution while you have the house on the market and leverage the T-Mobile solution temporarily in the son’s apartment until you resolve the sale and no longer need the cable solution at the house. You can use the T-Mobile home internet gateway solution, assuming there is T-Mobile home internet service at your son’s apartment without a contract and have the flat autopay $50/month and then cancel at any time and return the T-Mobile gateway. 

I assume the equipment from the cable company has a contract and fees and what not so why spend extra time fighting with things if you don’t have to. Turn the solution around just a bit and it is a win.

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Unfortunately, my son’s cable internet service is already scheduled to be moved to his apartment in October 25th.  So I’m stuck with this TM cellular modem.  I have a solution though!  I will deploy a Windows 10 desktop in the townhouse with a Team Viewer running in it.  I can always connect to the Team Viewer in that desktop and will be able to hop into my LAN in the townhouse.

 

Do you know if AT&T’s cellular Internet service is the same as T-Mobile’s?

 

Thanks.

iTinkeralot
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So, keep in mind due to T-Mobile’s CGNAT you will NOT be able to initiate an outside to inside remote connection due to the firewall rules and port blocking. If you keep the Team Viewer session standing with an external destination it might be a solution but I sort of guess maybe not. It is hard to say for sure until it is tested. I worked for HPE for 22 years as a network escalation engineer for enterprise customers so I might tend to imagine possible issues. I consider the variables. I dont know how long a Teams viewer session can be left open. I think it might be a challenge.

I have no experience with AT&T’s cellular internet solution. It was not an option in our location here. Our options were HughesNet (no way) or T-Mobile and the cellular solution. One thing you might look into is to connect into their community forum and get some feedback. You could look at the major topics and do some searching to see if their customers are any more satisfied. Reddit would be another source where you could get some info. Ah yes and there is Nater Tater and his YouTube videos. Maybe he has done some investigations with their gear. I am not sure. 

If they would delay the scheduled move I still feel that would be a better KNOWN solution with a much greater chance of success. I do understand the situation. 

iTinkeralot
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To answer the Teams question:

How long until Teams shows away? Your active status on Microsoft Teams will time out and go to “Away” after 5 minutes of inactivity. How do I change the inactivity timeout in Microsoft Teams? There is no way to change the inactivity timeout; all you can do is make sure your status remains active.

https://www.androidauthority.com/microsoft-teams-keep-status-active-3147225/

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It is “Team Viewer” NOT Microsot Teams!

 

 https://www.teamviewer.com/en-us/

iTinkeralot
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OK so an improved animal. That could be totally workable. I have never used it so I cannot say but it seems to be business oriented so probably will do what you want.

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I can traverse the CGNAT (whatever it is) from remote to my Windows 10 desktop running Team Viewer inside the AC1200 modem/router LAN.  I have done this already in my Lab.  I had to do this scenario in my Lab and it works!

iTinkeralot
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CGNAT is carrier grade NAT which is the network construct T-Mobile uses to allow the private addressing to public addressing. There are some things that do not work so well with their solution. Some things work fine but others not so much. It does present some challenges and obstacles for some users. If you have tested across with the T-Mobile gateway solution then you should be good to go. 

Sorry, it was not clear how deep your investigation has gone. Looks like you are doing your homework.

iTinkeralot
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Ah! You are using the Cudy AC1200 Router/Modem unlocked 4G LTE solution?

iTinkeralot
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You stated, 

“Why is there two IP addresses shown on the Cellular status field? Example: the Public is 172.58.207.82 then there is an “IP Address” of 172.32.84.244.  AND when I check my IP Address from a whatismyipaddress.com, it gives me 172.58.207.41!!!  Why is that???”

You might need to check with T-Mobile on their NAT solution with that service. My guess is that there is not a static IP address associated but there is a pool of addresses and the external router address on the outside NAT interface IP might change and not be fixed. That is a question to ask of T-Mobile and get an escalation engineer to clarify how that is going to work.

iTinkeralot
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So you can pretty easily determine if your solution is working through CGNAT. I am pretty sure the answer is yes but in your test solution you can determine this with the steps below.

  1. Open up a web browser.
  2. Type What is my IP in the URL bar.
  3. Hit enter.
  4. The browser will display your public IP address on top of the screen.
  5. Note down this IP address.
  6. Now log into your router’s settings by typing in the router IP in the URL.
  7. Use your username and password to log in.
  8. Navigate to the Status page.
  9. Here you can check the ISP-assigned WAN IP address.
  10. If both IP addresses are the same, then you are not on CGNAT.
  11. However, if this WAN IP differs from the public IP address, you are behind CGNAT.

Reference: https://www.purevpn.com/blog/what-is-cgnat/

iTinkeralot
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172.58.207.82 then there is an “IP Address” of 172.32.84.244.  

If you trace route out from a local client the first few router responses should help clarify the path and IP addressing.

IP Address from a whatismyipaddress.com, it gives me 172.58.207.41 < WAN IP.

I can see 172.58.207.41 is from a public class B,  IPv4 address range

Private Class B network, 172.16.0.0 – 172.31.255.255 (172.16/12 prefix)

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So I am on CGNAT.  Looking at the second paragraph on my original post:
Public: 172.58.207.82
IP Address: 172.32.84.244
whatismyipaddress.com: 172.168.207.41

The Public and whatismyipaddress.com addresses are not the same.

As I have stated, I am able to gain access to the inside LAN via the Windows 10 desktop with Team Viewer.  This setup will be implemented on Monday, October 24, at location.  I’m currently 1,800 miles away in my Laboratory.

iTinkeralot
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So it looks like you are good to go. 

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