OpenVPN - redirect-gateway not working

Question

I setup a OpenVPN server (VPN ip=10.8.0.1) on a Server with public ip. And I have a workstation(Ubuntu) in my laboratory with school ip that can access intranet resources of school.

I want my Android Phone and Windows PC can access the that resources. So I:

• OpenVPN server config:

  dev tun
  topology subnet
  server 10.8.0.0 255.255.255.0
  client-config-dir /etc/openvpn/server/ccd
  push "route 10.8.0.0 255.255.255.0"
  push "route-gateway 10.8.0.3"

• Connect my workstation to server and get a ip 10.8.0.3, its ccd config (equivalent to client config ) is:

  ifconfig-push 10.8.0.3 255.255.255.0
  

• In workstation, used iptables and added some items:

  $ sudo iptables -t filter -S
  -P INPUT ACCEPT
  -P FORWARD ACCEPT
  -P OUTPUT ACCEPT
  $ sudo iptables -t nat -S
  -P PREROUTING ACCEPT
  -P INPUT ACCEPT
  -P OUTPUT ACCEPT
  -P POSTROUTING ACCEPT
  -A POSTROUTING -s 10.8.0.0/24 -o wlx0810752b55c9 -j MASQUERADE

• The ccd config of my pc at home is:

  ifconfig-push 10.8.0.5 255.255.255.0
  push "route-gateway 10.8.0.3"
  push "redirect-gateway def1 bypass-dhcp"
  push "dhcp-option DNS 8.8.8.8"

• Result1 The pc cannot connect to internet. The route table of that pc is:

  route print -4
  0.0.0.0 0.0.0.0 192.168.1.254 192.168.1.21 35
  0.0.0.0 128.0.0.0 10.8.0.3 10.8.0.5 291
  128.0.0.0 128.0.0.0 10.8.0.3 10.8.0.5 291

the latter two item is what "redirect-gateway def1" added, without remove the original default gateway. I am curious that why def1 works to redirect traffic? Because the original default gateway is still there and with a better metric, thus no traffic would go through VPN.

• Result 2 My Android Phone cannot too.

  $ busybox ip route show table all
  default via 10.183.93.203 dev ccmni0 table 1002
  default dev tun0 src 10.8.0.4
  10.8.0.0/24 dev tun0 table 1015
  10.8.0.0/24 dev tun0 src 10.8.0.4 ...

I made sure that the workstation didn't receive the traffic:

$ sudo tcpdump -i tun0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tun0, link-type RAW (Raw IP), capture size 262144 bytes
^C
0 packets captured
0 packets received by filter
0 packets dropped by kernel
$

I have go through much topics about this with no working solution. So, anyone can help me, any suggest is appreciated!

Answer 1

In the ccd directory in the server the workstation file should contain iroute Try that please, I'm trying to do the same thing without using the access server and using a linux client as gateway as shown here https://www.youtube.com/watch?v=b7qr0laM8kA