My network setup is:

  1. First router+modem connected to ADSL cable
  2. Second router is connected via LAN to WAN to the first router
  3. My computer is connected to the second router via ethernet cable.
  4. there is no configuration on the first router i just connected the second router with ethernet cable to the first router.

My question is if someone has access to the network of the first router+modem can he eavesdrop on my computer's communications?

And if the answer is "yes", is there something I can do when I believe that the first router that is connected to the internet has very poor security, especially against man in the middle attacks?

The first router is from my ISP and is very cheap, without many options in the web panel. I can't replace it because my home telephone is connected to it.

the Wifi in the second router are disable i connected only via ethernet cable.

closed as too broad by Xander, forest, M'vy, NULLZ, Teun Vink Jun 29 '18 at 15:23

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • "Access" being what, exactly? – forest Jun 22 '18 at 17:47
  • Can you confirm that this is the basic layout of your Internet (numbers are relevant to figure out what connection segment/area you're focusing on in your question): INTERNET <--(1)--> [ADSL Cable Router/Modem] <--(2)--> [Secondary Router] <--(3)--> [Computer] And if so, are you asking this: if someone connects to (2) can they can eavesdrop the communications that actually go outbound from your computer? – Thomas Ward Jun 22 '18 at 18:12
  • "Access" being what, exactly? i live in cyprus small country + the ISP technical support run by 18 years old boys so i am afraid of WiFi password leak + or trying brute force my wifi password cant make more than 8 digit password my family get mad and cant do guest wifi dont have option on this router – justlinx69 Jun 22 '18 at 18:22
  • @Thomas Ward i mean by unauthorized access to my first network of the router+modem that connected to the internet – justlinx69 Jun 22 '18 at 18:25
  • 1
    @justlinx69 "Wifi password leak" where? Your secondary router which your computer actually plugs into? To bruteforce your wifi they would have to be within signal range of your network to brute-force the wifi. If they aren't within wifi signal range they can't bruteforce it... – Thomas Ward Jun 22 '18 at 18:27

I assume that the wifi you are connected to is an access point hosted on the second router.

If your second router is running a properly configured firewall, the answer is "no"; an attacker who breaches your ISP-provided first router will not have direct connectivity to your computer. He would be in a position to eavesdrop on any unencrypted connections going from your computers to the Internet (HTTP is not safe, but HTTPS is.)

As far as your WiFi security goes, be sure you are using WPA2, and don't use a trivially easy-to-guess password (don't use your names, etc.) Instead of a password full of hard to remember symbols, try a silly two or three word combo, like "CloudRapidOlive"

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