what happens internally in a router when lan is configured?

Why would a directly connected PC to the ISP get a DHCP address while the router can't? (Also, this happens only at night!). The Router is a TP-LINK Model No. TL-WR940N  router.

• The router successfully gets a DHCP address from the ISP during the day  and works smoothly, but around 7PM it fails until the early morning!  not sure how such a case can be investigated without buying a new router to test! I tried to connect a PC instead of the router, and it successfully acquired an IP address, but the router just fails until the early morning! Resetting to the factory defaults also does not help.. but in the morning it is back to normal! Here is the Access Control setting of the router: Host Settings: Schedule Settings: Target Settings: According to the Above I would assume that there should be no disconnections at a certain time like in my case.. Also please note that the router itself is who fails to get a public IP from the provider, not the devices inside the LAN, those do get a private IP from the router but fail to access the internet due to the router having no public IP from the ISP.

• Answer:

  You may want to look at your router settings.  Depending on the brand of router, there are settings for disabling connections external to the local area network (LAN).  These can be set by time.  It can also be fine tuned to deny only certain local IP's or MAC's from accessing the internet. I can give you examples, but, again, it depends on your model.  You will need to look for access settings that allow or deny. You will need to connect to your router's OS from a computer.  If you don't know how to do this, find your manual or look the instructions up on the makers website. If you can't find the problem settings, try resetting the router to default.  This will set it back to the factory default, and you will have to go through the steps of setting it up again, but it should clear out any problems. Post Edit:  Details of router is that it is a TP-LINK Model No. TL-WR940N.  There are 2 versions, and I am working with the manual for V1, since there is usually little difference in how access is controlled. First, if you don't have the manual handy, go to this link and download... http://www.tp-link.com/resources/document/TL-WR940N_V2_User_Guide_1910010921.pdf Go to section 4.11 (Access Control).  In the Router OS, look for Access Controls.  In the main screen, there should be a check box for "Enable Internet Access Controls".  If this is checked, uncheck it. Go through each of the options and see if there are any entries.  If there are, delete them.  There should be no hosts, targets or schedules and any rules that remain should be DISABLED. If the problem still exists, try the reverse,  Create a rule to ALLOW internet access 24/7, specifically for your, and any other connected, device.  There may be a glitch in the OS that is enforcing the rule outside the accessible settings. If you do this, you will need one of two things, either create a static IP on any computer in the house, or set the rules based on MACs, which can be discovered using the IPCONFIG /all command in the command prompt (which you may need to open as admin).  Your MAC is an 6 section address in HEX that looks a bit like this... A1-B2-C3-45-DE-6F If you have any non pc items, like a printer, console game unit or ROKU, you can usually find the MAC printed on a label. Creating a rule to allow unfettered access may clear up your problem.