y - Net Developer

amrameshreddy.blog.com376 CHAPTER 12 ■ DEVELOPING PEER-TO-PEER APPLICATIONS WITH WCFramrameshreddy.blog.com1. Click Start ➤ Control Panel ➤ Security.2. Under Windows Firewall, select Allow a Program Through Windows Firewall.3. Click the Exceptions tab.4. Check Windows Peer to Peer Collaboration Foundation.5. Click OK.Windows P2P NetworkingMicrosoft introduced the Windows peer-to-peer networking stack as a developer platform inWindows XP SP1. This stack is not installed by default; to install it on Windows XP (with SP2),you need to select the Peer-to-Peer option as part of the Networking Services within theWindows components that are available via the Add/Remove Programs option in the ControlPanel. If you have only Windows XP SP1, then you need to install the Advanced NetworkingPack to get the peer-to-peer networking stack.Figure 12-1 shows the architecture for P2P networking as defined by Microsoft. Thesignificant components that make up this stack are graphing, grouping, Name ServiceProvider (NSP), PNRP, and the identity manager. It is worth pointing out that this stack isunmanaged code with only a subset of the functionality exposed via WCF.GraphingFlood &SynchronizationStoreGraph MaintenanceFigure 12-1. Windows PNRP, graphing, grouping, and identity manager networking architectureIdentity ManagementGroupingGroup SecurityGroup SSPWinSock APITCP/IPPNRPIdentityManagerCrypto APIramrameshreddyramrameshreddyP2P solutions usually do not use DNS because of the transient nature of the mesh. In theory,using Dynamic DNS is an option, but in actuality few DNS servers on the Internet support thisin the real world. This raises an interesting question about how to resolve peer names to theirnetwork addresses (including ports, protocols, and so on). To allow this, Windows P2PNSP