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Preface: I am a web developer, and have a web application that is going to be served locally on a LAN for a client. I have never setup an individual access point, and have only really worked with those all in one Router/AP from Comcast type things.

Let's say I have a router running at 10.1.10.1, that also has a wireless access point plugged into one of its LAN's ports. Through that wireless access point, there are about 10 devices that need to connect to it.

I have an Intel NUC that has Ubuntu installed on it, where it hosts a React/Python application via Apache. All that needs to happen, is when someone types in 10.1.10.37(What I plan on setting the static ip of the NUC to) into a web browser, they should see the application.

The first thing I am confused about, is how are those devices assigned IP addresses? If the wireless access point is in AP mode, does the router actually do the DCHP assignment?

Let's say laptop on AP with IP address of 10.1.10.25 types in 10.1.10.137 in the address bar of Google Chrome, does this request get sent back through the AP to the router, where is then rerouted back to the AP? Or would the AP keep a pool of IP addresses and know where to send it to?

This sort of thing is not my area of expertise, and I would appreciate any help I could get. I would be glad to refactor my answer, as I feel I am misunderstanding some key pieces of LAN technology.

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Depends on the configuration of the AP.

In this case I would recommend to setup the AP as a bridge. In bridge mode you can think of the AP/WiFi as a cable: Everything is just the same as in a cable network - the AP "converts" all packets from the wireless interface to the ethernet and back. No routing, no DHCP no nothing, besides the same existing things on your LAN.

Let's say laptop on AP with IP address of 10.1.10.25 types in 10.1.10.137 ... rerouted back to the AP?

Conversion happens at Layer 2, at the "MAC Layer". Thats one layer below IP - Routing happens just on Layer 3, where Packets do have IP-Adresses.

In this case the MAC-Address of the Laptops wireless-interface would send the Request to the AP, the AP converts 1:1 it into a LAN-Packet on the cable and it would reach the server unchanged. No need to cache a pool of anything.

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    Thanks for the well explained answer. Its important that I mention that the "server", also connects to the AP. For example, say I am on a tablet connected to the AP, and type in the static ip of the server into my browser. Under the hood, the server and the tablet are actually communicating via mac address? – Dan Zuzevich Oct 12 '17 at 11:58
  • Yes. Technically it's called "ethernet" and ethernet is the transport layer of (in this case) IP. – bjoster Oct 13 '17 at 13:50
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There are so many possibilities for your situation that an answer could be quite long.

I will give you a short answer.

If your Access Point is in "dumb" / "simple" AP mode, then (after connecting to the AP Wi-Fi) it is no different than plugging the device into the network with an Ethernet cable. Whatever DHCP server you are using on that network (presumably the one on your router) will continue handing out local IPs as normal.

The caveat here is that very few things come out of the box in "dumb" mode these days. It is very likely that your AP will have many other features available and possibly enabled out of the box, like its own DHCP server. You will have to make sure that DHCP server is disabled or you will have conflicts. It is unusual for a basic network to have more than one DHCP server, though more advanced networks can have more than one for redundancy, but this requires more advanced configurations.

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The first thing I am confused about, is how are those devices assigned IP addresses? If the wireless access point is in AP mode, does the router actually do the DCHP assignment?

Devices on Wi-Fi get assigned addressing the same way they do on ethernet: either statically configured, or automatically, e.g. DHCP.

DHCP is served by a DHCP server. Some network devices may have a built-in DHCP server that you can configure, or you can have a stand-alone DHCP server on your LAN.

Because DHCP uses broadcast for requests, DHCP doesn't normally cross between LANs. You may be able to set up a DHCP relay on a LAN to facilitate having a DHCP server on a different LAN.

Let's say laptop on AP with ip address of 10.1.10.25 types in 10.1.10.137 in the address bar of Google Chrome, does this request get sent back through the AP to the router, where is is then rerouted back to the AP? Or would the AP keep a pool of ip addresses and know where to send it to?

This really has nothing to do with DHCP or address assignment. The traffic in your scenario may be bridged or routed, but without a network mask, it is impossible to tell. Routers route packets between networks, and bridges (switches WAPs, etc.) bridge frames on the same LAN.

For example, if the network mask is 255.255.255.128, your two addresses are on two different networks, and to get from one to the other would require a router to route the packets between the two networks. On the other hand, if the network mask is 255.255.255.0, then both addresses are on the same network, and frames are delivered directly from one host to the other by the MAC address.

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