Question

Is it possible to assign a "static" IP to clients based on the username

Posted on November 2, 2020
Security Ubuntu 20.04 VPN Ubuntu
Asked by Goran Blažič

Connected Tutorial

This question is a follow-up to this tutorial:

How to Set Up an IKEv2 VPN Server with StrongSwan on Ubuntu 20.04

First, love the tutorial, thank you very much. I’d like to always assign the same IP to specific clients, is this possible?

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Jamon Camisso

DigitalOcean Employee

• November 5, 2020

Accepted Answer

So, following up on previous comments and reading the Strongswan docs on Responder Configuration in a bit more detail, it sounds you can configure clients with static IPs using this setting on the server:

rightsourceip=%config

Along with this setting on the client based on the Initiator Configuration option that I mentioned previously:

leftsourceip=<your desired static ip here>

The commentary on the responder section states that:

Alternatively, the responder may define the following to let the client choose an address. This is not recommended if the client is not completely trusted.

Since it sounds like you trust all your clients, try specifying a static IP in the client’s leftsourceip setting. The rightsourceip=%config should ensure that Strongswan will accept the client’s request.

Do note that you’ll need to keep track of which client has which static IP, since Strongswan won’t be keeping track of which is assigned or duplicated.

Sri Charan Madhavapeddi

DigitalOcean Employee

• November 3, 2020

Hello,

In general, the moment you create a Droplet, you will be assigned an Static IPv4 address automatically. Similarly, when you destroy the Droplet, the IP address will be disassociated and will join the IP pool table. There is no way you can have one more Static IP address to the Droplet or assign/retain the same Static IP on our platform. Really sorry for the inconvenience!

However, you can use the provision of Floating IP on our platform. This allows you to assign one more IPv4 address and can also be moved between Droplets in same account. Refer to below links, which provides some insights on Floating IP:

https://www.digitalocean.com/docs/networking/floating-ips/ https://www.digitalocean.com/docs/networking/floating-ips/how-to/

You can also start using IPv6, request you to refer to below links:

https://www.digitalocean.com/docs/networking/ipv6/ https://www.digitalocean.com/docs/networking/ipv6/how-to/

Hope this helps!

Regards, Sri Charan