VPN Infrastructure Lab and Server Specifications

securityfox

I am looking to set up a VPN server (using OpenVPN) that is meant to allow multiple contractors to VPN-in those who will perform several tests against client's applications and networks. The nature of tests could involve running various network scans or application-level testings. I am looking for server and lab specifications to accommodate such need. I assume the cloud-based setup could get expensive due to the amount of traffic that will be generated. Therefore, I am looking to set up an on-prem or in a datacenter. The immediate need is to support at least 10 - 15 contractors traffic but I am looking something that can be scaled to meet the demand of at least 50 such contractors in about a year - two time. Please suggest the best server specifications, along with any other related infrastructure requirements such as a router, traffic requirements etc.