Skip to Main Content
Software as a Service (SaaS) has been adopted in a fast pace for applications and services on software clouds. However, the success of SaaS in software cloud cannot obscure the integration challenges faced by developers and enterprise infrastructure IT. Among those challenges, firewall/NAT traversal and security issues often pose a serious bottleneck as enterprises may not be entirely comfortable running mission critical applications outside the corporate firewall. On the other hand, SaaS applications in the cloud need to access enterprise on-premise applications for data exchange and on-premises services. The current approaches through opening special pin-holes on firewall or using dedicated VPNs have encountered a number of limitations and drawbacks. This paper presents a Proxy-based firewall/NAT traversal solution for SaaS integration (PASS). It allows SaaS applications to integrate with on-premise applications without firewall reconfiguration, while maintaining the security of on-premise applications. In addition, this approach is platform and application independent, making the SaaS integration seamless. Moreover, PASS is consistent with the enterprise web browsing infrastructure, and it requires little or no change to enterprise firewall/NAT configurations. In this paper we present the architecture of PASS and address SaaS integration challenges in software cloud, such as security/firewall, performance, and scalability. Experimental study based on our implemented system shows that the proposed approach of PASS is promising to resolve firewall/NAT traversal for SaaS integration with on-premise services.