Details of ifconfig-pool-persist

One of the options available in OpenVPN that can lead to a lot of confusion is ifconfig-pool-persist. This directive tells the OpenVPN server to maintain a persistent list of IP addresses handed out to different clients. When a client reconnects at a later time, the previously-used address is reused. This is only one of three methods for assigning static addresses to an OpenVPN client. The other two methods are:

• Using an ifconfig-push statement in a client-connect script

• Using an ifconfig-push statement in a client-configuration file

both of which take precedence over the entries found in the ifconfig-pool-persist file. Experience has shown that it is often a good idea to temporarily disable this option when an OpenVPN setup is not working properly.

In this recipe, we will demonstrate how to use the ifconfig-pool-persist and what the pitfalls are.

Getting ready

We use the following network layout:

Set up the client and server certificates using the first recipe...