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Author Topic: Cross LAN alert chat app  (Read 985 times)

Weaver

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Cross LAN alert chat app
« on: October 13, 2018, 02:03:51 AM »

I think I should get some iOS app that works directly across a LAN only, and can send an alert to another machine, simple as that. That way I could poke Janet’s iPad or iPhone from my iPad over the LAN to get help, even if there is no internet connection because of an outage. I don’t know if iMessage works with no internet connection.

I do have an iPad app that can do file-transfer over a LAN directly, but that is all it does and both ends have to be started manually, it is not listening all the time.

A suitable app could use link-local addresses perhaps, or even use MAC addresses only, no IP, but IPv6 link-local addresses would be fine and are always workable. Some use of multicast would be very nice, to locate correspondents easily.

I have been misusing the ‘find my iPad’ thing for this in desperation, because it can contact her iPhone or iPad and cause it to make a very loud noise so it is ideal to get help. It even works over the mobile network as well as over the wireless LAN. I have not tested this with the main internet connection turned off though. If it uses some kind of broadcast then all would be well, but if it feels that it has to contact Apple servers for some daft reading then it is never going to work reliably in a lot of different situations. The target machine has to be connected to some kind of network clearly, as you cannot just create an ad-hoc-mode (non-infrastructure) WLAN on the fly because the target machine will not know that it has to participate in such a set up, also the two machines might not be close to one another, but if the initiating machine uses link-local communications directly across directly across the current LAN as well as using the wider internet and trying to reach the target at every one of its mobile and WLAN IP addresses, then that is all an improvement in reliability, one more chance of avoiding things blocking success.

( There was an excellent app, can’t remember the name, included in Windows Vista which could create an ad-hoc WLAN in the middle of a desert, in a hotel foyer, or airport or anywhere so that a group of laptops could start talking to one another without access to an infrastructure mode WLAN in that location. But that was for participants who could actively start it up on each machine and who knew they were wanting to communicate. Also it was only meant for a group of machines physically close together, they had not made it general enough to also include other random machines on the internet, which was an omission. )
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dee.jay

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Re: Cross LAN alert chat app
« Reply #1 on: October 14, 2018, 02:00:15 PM »

You could run an XMPP server? I have one at home to keep in touch with my dad. It was the closest solution I could come up with after MSN Messenger shutdown
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Weaver

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Re: Cross LAN alert chat app
« Reply #2 on: October 14, 2018, 10:39:11 PM »

I will look into that. Read something about this a long time ago.
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