@ImtiazAli Which numbers do I put into the "internal port" and "external port"?

@ImtiazAli 

From what I read in Roomba FAQ, they need outbound ports opened on firewall. The document you shared is for opening inbound ports on Deco router firewall.

@Alexandre. How do I open the outbound ports on the firewall? 

@b00rdly 

I have found for you a useful guide in how to find if outbound ports are blocked. That should be the first step in troubleshooting. See this link: https://itigic.com/how-to-check-if-my-firewall-blocks-outbound-ports/

From that article:

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The way to check if you are blocking the ports in the outbound direction is very simple, in the address bar of our browser we will write http://portquiz.net:XXXX . The only thing that instead of XXXX we will replace them with the corresponding port to check. This way we could check if the output ports are really being blocked or we can use them normally.

Some examples that we could use are:

• http://portquiz.net:443
• http://portquiz.net:8080

-----------------------------

You can do that in browser on any device that is connected wirelessly or by Ethernet to Deco. Try that with all four ports you listed, one by one. 

To verify that you are doing testing right: the link http://portquiz.net:443 should always return success, because port 443 is HTTPS (secure HTTP) which no household router will ever block. So, start tests with that port and if successful - continue with other three. If unsuccessful with 443, you are not doing something right and that will require close investigation.

Example of successfully opening this link, on my computer (first few lines of Web page):

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Outgoing port tester

This server listens on all TCP ports, allowing you to test any outbound TCP port.

You have reached this page on port 443 (from http host header).

Your network allows you to use this port. (Assuming that your network is not doing advanced traffic filtering.)

Network service: https
Your outgoing IP: 

@Alexandre. Oh wow, thanks! This is really helpful. So i've tried it and 8080, 443, and 8883 worked but 123 didn't. This means that the ports isnt the problem right?

@b00rdly 

Does not look like ports issue. Have you enabled UPNP in Deco as recommended by @ImtiazAli ?

Other than that, if you have Main Deco connected to ISP router, it would make sense to test bypassing Deco mesh completely: turn on WiFi on ISP router, try connecting Roomba to ISP Router WiFi. That will decisively point at where the problem is.

@b00rdly 

Thinking about that from the other angle.

You may wish to contact iRobot Support with that issue. I've been on Deco forum for about a year, can't recall anyone raising an issue with Roomba WiFi. Meaning, TP-Link might not have enough information to assist.

At the same time, iRobot site has separate page with list of incompatible or partially compatible routers: https://homesupport.irobot.com/s/article/10657

Deco is not on that list, but web page existence means, they at iRobot track Roomba WiFi issues closely. If you contact them, explain what network setup you have, they might give you list of tests to run from inside your home network. They might even have Windows or Andriod app they can ask you to install to run tests from inside your home network. 

Because, you know, the best way to find what is blocked, is to run tests from inside. TP-Link can't be able to do that, as they may not know what exactly Roomba needs for networking connectivity. iRobot FAQs is not enough.

Also, if iRobot Support is helpful and managed to fix the issue or expose it, please share that information here. I myself own Roomba, an older one without Internet access. Eventually, I am going to replace it with newer model and would love to know what is needed to make it work with Deco WiFi mesh.

That information will also be helpful to TP-Link support, who check this forum, and other Roomba owners with Deco mesh.

@Alexandre. Yeah I already enabled UPNP and my Main Deco is connected directly to the modem. I hooked up my TL-WR802N 2.4g router to my deco system and the roomba successfully connected to the 2.4g router. Perhaps a simplier router works better with wifi appliances.