Google Fi + Wireguard Issues

VPN
1

RESOLVED For anyone in the future who runs into this, try the server’s IP address instead of a dynamic domain or an actual domain name. I am not sure why the wireguard windows client will replace the domain with the raw IP when you connect, but the android client does NOT do that yet. Thanks to /u/currentmudgeon

I was not having this issue until switching from Verizon wireless to Google Fi. Device is a OnePlus 10 pro.

I normally use an always-on VPN with wireguard to a server at my house or one of my VPS’s. I’m having an issue where it seems like when I’m driving and the cell tower switches I lose all connectivity until I disconnect and then reconnect the wire guard client. I never had this issue before and I have not played around with any of the MTU or keep alive settings in wireguard.

I’m not making this post in the wireguard subreddit because it seems to be an issue with Google Fi seeing as the issue was not occurring before I made the switch about 2 weeks ago from Verizon wireless to Google Fi.

Has anyone else ever had an issue similar to this or this exact issue?

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I use wireguard and have fi

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That’s how I roll too.

Do you use the built-in android "always on" setting? If so, I wonder if that, or the “block connections without von” setting somehow screws with handshakes or something.

I use Tasker to enable the vpn when I leave the house and disable it when I get back home.

4

TL;DR: Are you using hostnames or IP literals for your server addresses? With hostnames, you might have issues when switching from an IPv6/dual stack network to an IPv4-only one. Have you tried just using IPv4 addresses?

(BTW: How’s wireguard on android? Is battery life overhead decent? IIRC there’s kernel support but no Android API support yet for wireguard VPNs?)

Wall of words follows:

OpenVPN, not wireguard, here, on own VPS-hosted servers. I’ve had to diagnose my share of VPN problems on both WiFi and mobile (Fi and otherwise):

  • Usually MTU-related issues manifest as performance either slowing down drastically or “grinding to a halt”, e.g. a web page loading partially then stalling. This was finally addressed by setting TCP MSS to 1280 on the client app.

  • “Sudden” loss of connectivity, like you’re describing: This turned out to be an interesting combination of issues:

    • There was a bug that manifested on IPv6-only (usually mobile) networks that prevented the client from connecting when using IPv4 literals. This got fixed some months ago (Feb update?).

    • But. When specifying the servers with hostnames, even if your servers only resolve to IPv4 addresses, your client may still get an IPv6 address, if it happened to make the DNS query (start the connection) while on an IPv6-native network that uses DNS64/NAT64 for IPv4 connectivity. Mobile operators are increasingly going/gone that way. with their data networks.

    • Then, when you e.g. step into your local coffee shop with an IPv4-only LAN set to auto-connect, and if the client (like the OpenVPN one does) tries to “quick float” to the same IPv6 address instead of starting the connection from scratch, you get sudden no connectivity.

    • That’s what the OpenVPN client I use does (for “good” reasons, float can have other benefits when transitioning networks). So I’ve given up on hostnames for the servers completely, and only use IPv4 literal addresses.

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I can never get tasker to work right especially for wireguard stuff. I’m gonna try to disable the always on VPN Android function and see if that gets me anywhere

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I am SO sorry I didn’t see this sooner. I’ve been super busy and this fell by the wayside. Thank you so much. I’m going to start off using the raw IP address and not DDNS or hostnames.

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It took a little bit of work but I got it working a while ago. Send me a message if you want to see what I did.