tailscale exit node settings and global dns settings on pc, android termux or android shell

tailscale exit node settings and global dns settings on pc, android termux, android shell

0.In my 0th vps (for example Oracle Cloud free tier VPS, ubuntu 20.04, it allow me to create 2 free vps servers): 
    #sudo apt install tailscale(ref: https://tailscale.com/kb/1039/install-ubuntu-2004/)
    wget https://pkgs.tailscale.com/stable/tailscale_1.38.4_amd64.tgz
    tar zxvf tailscale_1.38.4_amd64.tgz
    sudo cp tailscale_1.38.4_amd64/tailscale* /usr/bin/
    rm -rf tailscale_1.38.4_amd64*
    sudo tailscale up    //copy the showed url and authorize google sign-in in the web  browser
    ip addr show tailscale0       //for example: 100.71.153.9

1. In my 1st vps(in china, for example my linux PC in my home):
     sudo apt install tailscale
     sudo sysctl net.ipv4.conf.all.forwarding=1
     sudo tailscale up --advertise-exit-node --accept-dns=false    //copy the showed url and authorize google sign-in in the web  browser
     //"--advertise-exit-node" to advertise this vps as exit node, "--accept-dns=false" to avoid global dns settings overwriting /etc/resolv.conf in exit node
     ip addr show tailscale0           //it shows for example: 100.71.153.10
     curl https://www.google.com/search?q=my%20ip   //it shows for example: 132.226.172.5
     tailscale version                      //it shows 1.8.6
     //open socks5 proxy 8086 that go through the 0th vps
     while true; do nohup /usr/bin/ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o ServerAliveInterval=10 -o ServerAliveCountMax=6 -CND 100.71.153.10:8086 [email protected] -p 22 > /dev/null 2>&1; sleep 1; done &
     //create socks86 interface for 8086 socks5 proxy
     while true; do nohup ip tuntap add dev socks86 mode tun user nobody >/dev/null 2>&1; ifconfig socks6 up 10.6.0.1 >/dev/null 2>&1; badvpn-tun2socks --tundev socks86 --netif-ipaddr 10.6.0.2 --netif-netmask 255.255.255.0 --socks-server-addr 100.71.153.10:8086 >/dev/null 2>&1; sleep 1; done &
     ./mydns --listen 0.0.0.0:53      //my udp dns server, output every query logs, china/foreign IP split, for foreign IPs: ip route add <foregin ip>/32 dev socks86 scope link

2.In the web page of https://login.tailscale.com/admin/machines
     Click the "..." menu button of 100.71.153.10
     Click "Review route settings"
     Enable the "Use as exit node"

3.In the web page of https://login.tailscale.com/admin/dns
    Click "Add nameserver", input "100.71.153.10" and click "Save"
    Click the "Override local DNS" switch and enable it

4.In my android phone:
   Install latest tailscale app from google play(version >=1.8.6)
   Authenticate it with google sign-in
   Click the "..." menu button on the top-right of the app
   Click "Use "Use exit node" and select the name of "100.71.153.10"
   Click "Active" switch
   Open the browser,
   visit  https://www.google.com/search?q=my%20ip
   It shows my 1st oracle vps's IP 132.226.172.5

5.In my 2nd vps(in china, just for test, not must):
   curl  https://www.google.com/search?q=my%20ip      //it shows my 2nd vps's IP: 152.70.90.2
  sudo apt install tailscale
  sudo tailscale up --exit-node=100.71.153.10    //to restore: sudo tailscale down ; sudo tailscale up --reset
  curl  https://www.google.com/search?q=my%20ip --resolve www.google.com:443:216.58.200.36     //it shows my 1st vps's IP: 132.226.172.5
  Now I can see "/etc/resov.conf" has  been changed to "nameserver 100.71.153.10"
  I can see dns query log in my 1st vps

================
socks5 proxy is more convinient than exit node:
in vps:
./tailscaled --tun=userspace-networking --state=./tailscaled.state --socket=./tailscaled.sock --port 41641 --socks5-server 0.0.0.0:8080
./tailscale --socket=tailscaled.sock up
in home pc:
time curl --socks5 <vps tailscale ip>:8080 https://1.1.1.1 | head -n 20

========tailscale in android termux========
in my linux PC:
$ wget https://github.com/termux/termux-app/releases/download/v0.118.0/termux-app_v0.118.0+github-debug_arm64-v8a.apk
$ adb install termux-app_v0.118.0+github-debug_arm64-v8a.apk

in termux in my android phone:
$ wget https://pkgs.tailscale.com/stable/tailscale_1.30.0_arm64.tgz
$ tar xzvf tailscale_1.30.0_arm64.tgz
$ ./tailscaled --tun=userspace-networking --state=./tailscaled.state --socket=./tailscaled.sock --port 41641 --socks5-server 0.0.0.0:8081
$ ./tailscale --socket=./tailscaled.sock up
$ pkg install openssh openssh-tool
$ sshd
$ passwd root

in my VPS (there's tailscaled in it already):
$ ssh root@<my android phone's tailscale IP> -p 8022

==============go webview in android termux===========
go get github.com/webview/webview        #installed webkit2gtk
env DISPLAY=:0 go run test.go
#view the ui with android-xserver(https://github.com/nwrkbiz/android-xserver), the apk size is only 0.25MB

==============tailscale in android without termux========
# in fact, tailscale doesn't need termux, to use "unix:abstract", for example "@tailscaled.sock":
./tailscaled --tun=userspace-networking --state=./tailscaled.state [email protected] --port 41641 --socks5-server 0.0.0.0:8081
./tailscale [email protected] up

================tailscale in github codespace===========
# add this line into the "start)" paragraph in /etc/init.d/ssh:
/usr/sbin/tailscaled --state=/var/lib/tailscale/tailscaled.state --socket=/run/tailscale/tailscaled.sock --port 41641