[ISSUE]Problems With Tailscale Subnet Access

[whitedavidp]

Describe the bug
I have just started using Tailscale so that my A12, rooted, Moto XT2215-4 can access my home LAN (192.168.1.0/24) over mobile data (Verizon) via a Windows 10 machine running Tailscale and advertising that subnet as a router.

I have been having intermittent connectivity issues and have been trying to search the cause down. What I can say so far is that the issue is definitely iptables-related and, if - after connecting Tailscale - I issue the command iptables -F; iptables -X, connectivity is re-established immediately.

Once I issue the above, if I apply the firewall rules inside of AFwall, the connectivity remains intact. So this does NOT seem to be caused by rules that AFwall is introducing.

Right now, I do the above using Tasker when it detects that the VPN is connected. And, so far, this seems to always work.

So somewhere, somehow, it seems as if one or more rules are added to iptables that mess things up.

Firewall Logs

Rules - Not Working.txt
Rules - Working.txt

Smartphone (please complete the following information):

• Device: Moto XT2215-4, rooted, of course
• Android OS: Stock A12

Additional context
To the best of my knowledge (which is obviously limited), nothing other than AFwall is manipulating the iptables. However, I supposed that something in Android itself MAY be doing something. But I have no idea what/where/when/why/how that might be happening.

Since my experience shows that clearing all existing rules and re-applying those configured via AFwall does NOT cause this Tailscale issue, this MIGHT NOT technically be an AFwall issue. But I have no idea where else I might go to try and identify what rule(s) specifically might be causing this.

I have tried to diff the attached files and I definitely see differences. But I am way too ignorant to decipher what those differences might be doing to my setup.

Thanks for considering this strange circumstance.

[whitedavidp]

In an effort to help nail things down, here are the rules shown by AFwall shortly after reboot with mobile data enabled (no wifi) prior to reboot. No interaction by me with anything save show rules, copy, pasted into a file:

Reboot Rules.txt

After doing nothing else but applying the AFwall and showing rules, copy, paste into a file:

After Apply Rules.txt

The above two files differ but not by any huge amount. I am not informed enough to speak to the differences but they are quite similar.

After starting Tailscale, issuing iptables -F;iptables -X from a shell in Tasker, and enabling Afwall via the Tasker plugin (I believe this is the same as tapping Apply inside the app since I had not disabled Afwall from inside the app at any point here) I get these results:

After Tailscale Rules.txt

Which seem greatly different than either of the two above results. Again, I cannot explain why or what these all mean. I really did NOT expect them to be so very different.

And BTW - I am using version 4.0.1 of AFwall. I have not enabled VPN permissions separately. And I have enabled Active Rules with no delay.

It is interesting to me that the description under Active Rules in the settings does NOT mention VPN in the list of connectivity changes. I do not know if this is an oversight or if VPN is expressly ignored for some reason.

Thanks!