Can't Join Home LAN From My iMac Yosemite 10.10.4, can I please get some help?

[iMore Question]

Can't Join Home LAN From My iMac Yosemite 10.10.4

I had previously set up a LAN myself that worked fine for several months as a private home network for my iMac Yosemite, my Win7 PC, my Win98 PC, and my Android Nexus 7 tablet. But, for some unknown reason, I can no longer login to the network from the iMac. Seems to want a password from the iMac, but not from the other computers on the network. All my diagnostic attempts have failed. On the advice of a couple experts, I would now like to "de-activate" the LAN completely, and create a new one over again from scratch. But I don't know how to do the "deactivation" part. Any advice, please? Thx.

 

[Branta]

Re: Can't Join Home LAN From My iMac Yosemite 10.10.4

LAN over WiFi? Two common problems, either
* you have an IP addressing problem (conflict or one device is trying to connect to a wrong network)
* WiFi authentication (password) has been forgotten in the problem device (you did setup wifi security, right?).

You don't say how your network is configured but I'm guessing you have some kind of DSL/cable box which provides the network addresses to your devices, and is the gateway to the outside world. Start with a simple reboot of this box, then check the password it expects to allow others to connect. This might even fix the problem, I've just had to reboot the office router again because it wouldn't let my phone see the outside world over WiFi.

If you have to force a complete new network this is the place to begin. Set a new SSID (network name) and password, make sure it is doing automatic IP addresses (DHCP is on) then go round all your devices and connect to WiFi using the new network name. Job done!