vpn is working but ip address not changing

Is there something we can check for this? It is a response from vpn using dynamic DNS connected but no internet (openwrt router as server).

When I connect to vpn and check my ip from whatismyip it is still the same as before connecting.

I am connecting to a friends wifi and the ip when I check it is the same as when i am connected to vpn.

route -n before vpn (at my home wifi):

 Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
192.168.1.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
192.168.1.153 127.0.0.1 255.255.255.255 UGH 302 0 0 lo

route -n before vpn (at my friends wifi):

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.254 0.0.0.0 UG 0 0 0 wlan0
192.168.1.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
192.168.1.2 127.0.0.1 255.255.255.255 UGH 302 0 0 lo
192.168.1.135 127.0.0.1 255.255.255.255 UGH 302 0 0 lo

route -n after connecting to vpn (through my friends wifi):

Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.254 0.0.0.0 UG 0 0 0 wlan0
10.10.10.0 0.0.0.0 255.255.255.0 U 0 0 0 tap0
79.1.... 192.168.1.254 255.255.255.255 UGH 0 0 0 wlan0
192.168.1.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
192.168.1.2 127.0.0.1 255.255.255.255 UGH 303 0 0 lo
192.168.1.134 127.0.0.1 255.255.255.255 UGH 303 0 0 lo

I am using a router with openwrt as server (192.168.1.1).

-----UPDATE---------

How to remove this?

Table: NAT
Chain zone_wan_nat (References: 1)
Rule # Pkts. Traffic Target Prot. Flags In Out Source Destination Options
1 834 57.26 KB MASQUERADE all -- * * 0.0.0.0/0 0.0.0.0/0 -

2 Answers

Here, you're only routing traffic destined for 10.10.10.0/24 to the "tap0" interface. "tap0" is a virtual/imaginary interface that linux uses to "fake" a layer-2 connection. So in your particular case, when you send a web request to whatsmyip.com or whatever, that particular traffic is going out your normal ethernet (eth0) interface, which means the service will do a DNS lookup and see your normal, non-tunneled IP address.

If you can, use the VPN connection to SSH or telnet or remote desktop or VNC or whatever to a computer that's on the 10.10.10.x network. Then from THAT machine, do a "whatsmyip" and you should see something different, because (presumably?) that computer will have a different default route to the internet.

Try adding the following option in the openvpn config file:

push "redirect-gateway def1"

This will force all your traffic to use the vpn tunnel to the vpn server on your home router.

If you run "traceroute " before connecting to the vpn and after connecting to the vpn, you will see that you will take different path, meaning traffic is going through the vpn.

If you want to see your home router public ip address (the no-ip domain name) on whatismyip.com when using the vpn, then you need to NAT your traffic on the router.

You can do this on your router via the command :

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

This command will translate the source IP of your traffic to the public ip of your home router, and thus whatismyip.com should give you your home ip next time.

If your wan interface is not eth0, and is eth1 for example, then you need to change it in the command, i.e. "-o eth1"