1. Create a folder called ccd inside /etc/openvpn/.

#mkdir /etc/openvpn/ccd

2. Add the following line to the openvpn server configuration file:

client-config-dir ccd

3. In /etc/openvpn/ccd/ you will create one file for each user you want to have a fixed ip address. You must name the file exactly as the “common name” of the user certificate file. If you don’t know what is in his “common name” just run the following command to find it. It is right on the top, look for CN=user.

# root@srv-openvpn:~/openvpn/keys# openssl x509 -in user.crt -text |grep -i 'CN='|grep -i "Subject"

PS: in case the CN name has white spaces the file name will have to be created using “_”. eg. CN=Leo B the file name will be Leo_B.
4. Once created open the file and add the following line:

ifconfig-push 10.10.80.100 10.10.80.101

Use your own network of course. You can add ordinary Openvpn parameters into this file if you want. For example you can push another gateway for this specific user.

5. Restart Openvpn server and check whether the user has acquired the specified ip address.
And there we go!

Good luck!
Leonardo Borda