topic Re: Client-to-Site VPN with strongswan in General Topics

Client-to-Site VPN with strongswan

M_Mtalsi — Wed, 27 Apr 2022 13:54:50 GMT

Hello,

Can we build VPN ipsec Client to site with strongwan in customer side.
We can't use globalprotect

Regards,
Mehdi Mtalsi,

Re: Client-to-Site VPN with strongswan

OtakarKlier — Wed, 27 Apr 2022 20:10:06 GMT

Hello,

Just to clarify, you want to use a 3rd party client to connect to the Palo Alto?

Regards

Re: Client-to-Site VPN with strongswan

BPry — Thu, 28 Apr 2022 00:35:54 GMT

@M_Mtalsi,

Assuming that you're talking about setting up a Site-to-Site IPSec tunnel between StrongSwan and the Palo Alto, this would be a standard IPSec tunnel setup. The last time I set this up we weren't able to get IKEv2 up properly and had to use IKEv1 only, but the client wasn't able to secure time with the vendor to troubleshoot further once things were operational so I didn't spend much time trying to figure out the issue or look at the StrongSwan side of things to see if they had made a mistake on their end.

Re: Client-to-Site VPN with strongswan

M_Mtalsi — Thu, 28 Apr 2022 08:03:12 GMT

@OtakarKlier Hello,

We want to set up a Client-to-site IPSEC tunnel between StrongSWan (= linux computer) and a palo alto firewall.

It is possible ?

@BPry thank you for your answer.

Regards,

Re: Client-to-Site VPN with strongswan

A_Astardzhiev — Sun, 01 May 2022 05:55:26 GMT

Hey @M_Mtalsi,

You may call it client-to-site, because StrongSwan is installed on endpoint host, rather on a host with ip forwarding enabled, but what @BPry explained is still technically a site-to-site, at least from PAN firewall point of you:

- You need to create IKE Gateway with public IP address of the peer

- Create tunnel interface and security zone associated with the tunnel assigned to this IKE gateway.

This means that only single device can establish VPN tunnel and only traffic with that devices will be associated with that security zone. If you plan to have multiple host installed with StongSwan - you will need separate IPsec tunnel for each StongSwan agent.

As you can see this approach is suitable if you plan to install StrongSwan on Linux machine and enable ip forwarding, so it can act as VPN gateway for multiple users on site.

If you want to use StrongSwan as client VPN, you will need different approach - GlobalProtect support 3rd party VPN clients, which includes StongSwan - https://docs.paloaltonetworks.com/compatibility-matrix/globalprotect/what-x-auth-ipsec-clients-are-supported

Because StongSwan is purely IPsec client and cannot authenticate like GlobalProtect agent (using HTTPS requests), you need X-Auth - https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA14u000000HAlICAW&lang=en_US%E2%80%A9

Benefit of this approach is that users with StongSwan clients will be treated like normal GlobalProtect remote users and will be associated with the same security zone, use same ip pool, etc. The biggest difference is that those clients will not submit HIP reports.