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Connecting to a WiFi network and a Wired network simultaneously

Posted: Thu Jan 10, 2019 9:33 pm
by gjwolfe
Forgive me if this has been asked before. I did a search and didn't find anything that I'd consider similar on the first 5 or so pages of results.

Here's the situation:

I'm working on setting up a RPi-based Plex media server in my travel trailer. I keep the camper parked next to my home and within range of my home WiFi. The RPi will be attached to a USB hard drive or some other mass media that is loaded with movies for the kids for rainy days. The RPi will also be connected via wired Ethernet to a wireless router in the travel trailer in order to stream to wireless devices as we drive to the campground (kids can connect their tablets to the camper WiFi and are able to access the Plex server running on the RPi). There is no internet access via this network...there are plans at a later date to install a WiFi antenna that can be setup while camping, but this will be broken down and stored while the trailer is parked in my driveway. All of that is easy enough...plenty of tutorials around to get all that set up.

The part that I need to hash out is basically a minor "convenience" item. Since everything will be wired into the camper's 12V system and during the summer months I leave the camper plugged in the RPi and associated LAN/router will be left powered on. I would like to be able to use that as an advantage since the RPi will be within the range of my home WiFi. When parked, I would like the RPi to join my home LAN over it's built in WiFi so that I can copy or delete movies to the attached media from my home network. I know it's not going to be that simple however since I will be essentially be trying to use the RPi as a bridge when it is connected to two different networks. I don't really need that functionality. In fact if there is some sort of script that I could use that would direct the RPi to disconnect from its wired network (via software) when it can connect to my home network over WiFi, that would be perfect. Technically, I could just unplug the router in the camper and be done with it, but if there is an easy way to automate this...that'd be super. One less thing to remember while getting ready to head out on the road would be awesome. This is still in the planning stages, but I'd like to have it figured out before I dive head-long into it. Has anyone else tried something like this? Let me know. Thanks in advance!


Re: Connecting to a WiFi network and a Wired network simultaneously

Posted: Fri Jan 11, 2019 10:20 am
by epoch1970
You plan on using a travel router as an access point.
If the Pi is a Pi3, in addition to the ethernet interface it has a built-in wifi adapter. You can configure this interface to connect to your home network.
If the Pi is another model, you have 2 options:
- change the travel router configuration from AP to client (to your home network)
- connect a machine at home to the travel router's network (assuming it would be in range as well)

Re: Connecting to a WiFi network and a Wired network simultaneously

Posted: Mon Jan 14, 2019 6:32 am
by gjwolfe
I am looking at the 3 B+ for that very reason. The wired network jack is to tie to an access point essentially. The on-board WiFi will be used to connect to my home network. My question is more, will this be an issue for the Pi as it will be connected to two different networks simultaneously. And if it will, is there a work around?

Re: Connecting to a WiFi network and a Wired network simultaneously

Posted: Mon Jan 14, 2019 2:23 pm
by epoch1970
No issue unless you choose the same IP network for the access point and your home, eg for both.
Use an IP network for your AP different from the one at home so the Pi won't get confused when connected to both at the same time.