Trong chương này, chúng ta bước thông qua việc triển khai các Nghị định thư Point-to-Point Tunneling (PPTP) và Layer Two Tunneling Protocol Internet Protocol Security (L2TP/IPSec) các giải pháp VPN site-to-site. Trường hợp có những phương pháp giống nhau cho việc triển khai cả hai lựa chọn, chúng tôi sẽ chỉ cho chúng ra và tham khảo thích hợp | 295 Chapter 12 Troubleshooting Site-to-Site VPN Connections In Chapter 11 Troubleshooting Remote Access VPN Connections we went through the extensive and involved procedures for troubleshooting remote access virtual private networks VPNs . The process for troubleshooting site-to-site VPNs is similar in many ways and uses the same procedures. We will go through the process in detail again for many areas so that you have a complete and comprehensive troubleshooting methodology to use. Where it doesn t make sense to repeat information we will refer to Chapter 11. In this chapter we list the set of troubleshooting tools provided with Microsoft Windows that you can use to gather information about connections and then describe what to look for to correct the most common problems with site-to-site VPN connections. Remember from the previous chapter the two things to keep in mind when trying to troubleshoot VPNs Divide and conquer. To isolate the problem rule out components individually and eliminate them from the troubleshooting equation. This troubleshooting stuff really works Don t get discouraged. Keep plugging away if you are having problems and make sure you work with all the tools available. Troubleshooting Tools As stated in Chapter 11 the Microsoft Windows Server 2003 family provides the following tools to troubleshoot VPN connections Transmission Control Protocol Internet Protocol TCP IP troubleshooting tools Authentication and account logging Event logging Internet Authentication Services IAS event logging Point-to-Point Protocol PPP logging 296 PART III VPN Troubleshooting Tracing Oakley logging Network Monitor We did an extensive overview of these tools in the previous chapter and won t repeat their uses here. For more information about these tools see Chapter 11. One new tool you need to be aware of for site-to-site connections is the Unreachability Reason facility which you can use to investigate a site-to-site VPN connection problem. When a demand-dial .
