I am looking for a setup where I have Freepbx installed at my home office, while using a softphone both on my computer and android phone (Nokia G11). Andoid support always on vpn, and the router got vpn server setup.
I am looking for others that have done this and if it was successful or not. I read a lot about issues with push messaging when someone call to the softphone using a mobile phone.
I am also looking for a subscription free softphone app that I could use. Any tip?
Yes, push notifications are going to have issues. This is because the push server can’t talk to your SIP server.
As for free softphones, there’s Linphone (if you don’t care about push anyway).
I always recommend Acrobits Groundwire - it does cost, but it’s a one off fee and in my opinion really worth it.
Just a warning though - I’m sure you’ve thought of this already, but if you tunnel all your traffic through your home router, it’s likely to slow down your connection, as well as other issues.
Your other option would be to use some kind of split-tunnel VPN, so only traffic to your internal network goes through the VPN. I use and recommend Tailscale, but ZeroTier is also a good, simple setup option.
If you’ve really got the time, patience and really want to do this, you could deploy your own push server at home, then recompile Linphone to use it.
Sangoma Connect free for the first year then 19.99$/year, everything else is a workaround
I have wireguard and asterisk running on a vps. My android phone uses the wireguard vpn always-on, and I use an app called Sipnetic to connect to asterisk. It works ok, but there’s no push messaging, so it does consume some battery. Still, my phone consumes less than 1% per hour overnight.
Thank you. I have fiber connection with good speed ans the phone will only be used for company phone/e-mail and such. I’ll check into how to have my own push server at home 
. I have checked Acrobit groundwire but thought is was for cloud based and not for my own freepbx. Is it possible to use the push server at home with Acrobit?
I don’t think OP wants the SIP to be accessible publicly (always best unless it’s really needed)
ACROBITS and Groundwire not the free version cloud and… The paid version is working fine with any pbx
No, you can only run your own push server for Linphone.
Groundwire can connect to any PBX and they provide their own push server. But you won’t be able to use push if the server is not publicly accessible.