Interoperability issues among various IPsec implementations

Most of the major providers of networking hardware and software came up with solutions for VPN connections. Companies use VPN connections in order to secure communications between branches or for remote workers. One of the most encountered ways of securing communications is to use IPsec VPN. This protocol uses cryptography in order to encrypt and authenticate the traffic flowing between points of interest. Actually, this is a large set of related protocols operating above the IP layer of the OSI stack, each represented by an RFC specification. It is very important that each vendor implements these specifications exactly, in order to be able to interoperate with other vendors and the IPsec access configuration is the one posing the most issues. This is because vendors have the liberty of implementing the access requirements as they consider, having to follow guidelines that are not restrictive. The paper summarizes the interoperability issues that appear when configuring IPsec on different vendor devices and draws a few conclusions on the level of interoperability, protocol compliance and best practices to adopt when deciding which solution a customer needs for his/her business.