Dumb AP / Access Point Only, client dhcp

Dumb AP / Access Point Only

https://openwrt.org/docs/guide-user/network/wifi/dumbap
says:


    1. Disconnect the (soon-to-be) Dumb AP from your network, and connect your computer to it with an Ethernet cable.
    2. Use the web interface to go to Network → Interfaces and select the LAN interface.
    3. Enter an IP address “next to” your main router on the field “IPv4 address”. (If your main router has IP 192.168.1.1, enter 192.168.1.2). Set DNS and gateway to point into your main router to enable internet access for the dumb AP itself
    4. Then scroll down and select the checkbox “Ignore interface: Disable DHCP for this interface.”
    5. Click “IPv6 Settings” tab and set everything to “disabled”.
    6. In the top menu go to System → Startup, and disable firewall, dnsmasq and odhcpd in the list of startup scripts.
    7. Click the Save and Apply button. Hard-Restart your router if you're not able to connect anymore.
    8. Go to http://192.168.1.2 (or whatever address you specified) and check if the settings for the LAN interface are the same.
    9. Use an Ethernet to connect one of the LAN ports on your main router to one of the LAN/switch ports of your “new” dumb AP. (There's no need to connect the WAN port of the Dumb AP.)
    10. You are done.

Would not it be batter to skip step 3. which is manually setting the IP address and DNS address, and allow Client dhcp odhcpd to continue to run. That way the router, or the admin of the router, could control the IP address and DNS address of the access point. That way, you can take your access point and plug it into an arbitrary network with DHCP and everything works. If the administrator of the router wants the access point to have a particular address and DNS address, he can use his standard dhcp server management tools to control it. I have had commercial access points and that is how it worked.
Thank You

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That's not what happens if you leave it running (on LAN at least).

  • This would leave two DHCP servers active on one broadcast domain. Since both devices are on the same network, this would not work.
  • Further, in most cases, the devices would have an IP address conflict if this step was omitted.

Maybe you meant this should remain on WAN...I just assume you understood these instructions are referring to LAN. If you used WAN instead, the clients would be on a different subnet.

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@pelliott has a point there @lleachii.
Instead of assigning a static IP, he could use DHCP protocol on the LAN interface, in case he wants to manage it from the DHCP server or move it to different locations. The DHCP server of the LAN is switched off in step #4, so there won't be multiple DHCP servers.
The tutorial is not covering all the scenarios, just giving a general guideline to an inexperienced user. Obviously if you know what you want and what you are doing, you can deviate from it.
On the other hand even if you relocate the dumb AP to another location, all the settings will continue to work for the clients, only the device itself will not be managed that easily.

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I am confused openwrt is running both odhcpd and dnsmasq. I know that dnsmasq can be a dhcp server. What is actually doing the the dhcp serving, odhcpd or dnsmasq? What i wanted to suggest was to turn off DNS serving, while allowing DHCP client to continue to allow the router to set the access points IP address and DNS address. That way, there would be only one dns server on the wan, that is, the router.

What actually does the DNS serving, odhcpd or dnsmasq? Is there any way to turn off DNS serving, but not dns client?

Thank You

True!

IPv4 - dnsmasq
IPv6 - odhcpd

You can turn them off by disabling it in the Interface section at the bottom, under DHCP.

Screenshot%20from%202019-10-15%2019-38-07

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Ok it is the udhcpc program that is the client. So I guest the answer is to turn off dnsmasq and odhcpd as the documentation says, and just omit step 3, manually setting the IP address and the DNS address. This will allow udhcpc to do it as directed by the router's dhcp on the wan. Plug the router's lan port into the access point's Wan port.

Unless you know what you are doing, you'd better use the LAN port for the access point to connect on the LAN port of the upstream router. Also use the DHCP protocol, instead of STATIC, on LAN interface.

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There is some script

sometimes as I'm setting up access points I wonder how many of the OpenWRT devices
are used as access points only.
out of 4 devices 3 of mine are access points the other is routing as well.
I wonder if it's worth making this easier to do with an alternate config or flash file
I think of this when reading about the 4M/32M being not enough room etc.
I would never use a 4M/32M device as a full router
but as to make use of something that would just going to the trash
using it as an access point in the shed to extend coverage into you yard
I think it's a great way to make use of it even if it's only a 100M/2.4G limited device
it's not like you need firewall's & dhcp servers in an access point