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Some Network Commands. Some useful network commands ping finger nslookup tracert ipconfig. Port Addresses. What is a port address? A unique number assigned to a network application as an address to receive or send data. Why need port addresses?
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Some Network Commands • Some useful network commands • ping • finger • nslookup • tracert • ipconfig
Port Addresses What is a port address? • A unique number assigned to a network application as an address to receive or send data. Why need port addresses? • A single host may run several servers, such as Web, FTP, Telnet, Email, etc. When the network layer receives a message, it needs to know which application layer software package should receive the message.
Application Layer Port Addresses • Port numbers are divided in three ranges: • Well-known ports: 0-1023,controlled by IANA • Registered ports: 1024-49151 • Dynamic or private ports: 49152-65535. We also call them ephemeral ports.
Application Layer Port Addresses • Default port number assignments • Web: 80 (or 8080) • FTP: 21 • News group: 119 (or 8119) • Telnet: 23 • SMTP: 25 • IANA (Internet Assigned Numbers Authority) is taking care this issue.
WINS • WINS (Windows Internet Naming Service) manages the association of workstation names and locations with IP addresses without the user or an administrator having to be involved in each configuration change. • WINS automatically creates a computer name-IP address mapping entry in a table. When a computer is moved to another geographic location, the new subnet information will be updated automatically in the WINS table. • WINS complements the NT Server's DHCP. • WINS have been submitted to IETF as proposed open standards. New features are included in the follow-on to Windows NT, Windows 2000.
Windows Network Model Windows Network Model Internet Model Layer 7 I/O Named Pipes Mail Server Application layer: FTP, TELNET, HTTP, etc. Environment Subsystem Layer 6 Provider Interface Layer 5 NetBIOS (Redirector) Transport layer: TCP, UDP Layer 4 TDI WINSOCK NetBEUI TCP/IP Layer 3 Network layer: IP NDIS 3.0 NDIS Environment and Drivers Layer 2 Layer 1 Data link layer Physical layer 802.2 802.3 802.4 802.5 NDIS: Network Driver Interface Specification
NDIS • NDIS (Network Driver Interface Specification) is a Windows specification for how communication protocol programs (such as TCP/IP) and network device drivers should communicate with each other.
NetBIOS NetBIOS (Network Basic Input/Output System) • Created by IBM for its early PC Network, was adopted by Microsoft, and has since become a de facto industry standard. • A program that allows applications on different computers to communicate within a local area network (LAN). • Used in Ethernet, token ring, and Windows NT networks.
NetBEUI NetBEUI (NetBIOS Extended User Interface) • Developed by IBM for its LAN Manager product and has been adopted by Microsoft for its Windows NT, LAN Manager, and Windows for Workgroups products. • A new, extended version of NetBIOS, the program that lets computers communicate within a local area network. • Formalizes the frame format (or arrangement of information in a data transmission) that was not specified as part of NetBIOS.
NetBIOS vs. NetBEUI • NetBIOS has 18 commands for PC connections. • NetBEUI adds 8 more and is used as a transport protocol. It is faster and more efficient than NetBIOS • When NetBEUI is in use, NETBIOS becomes API that invokes NetBeui. • They can support a LAN with less than 200 PCs.
NetBIOS over TCP/IP • NetBIOS over TCP/IP runs over the TCP/IP, so that you can share drives and printers over the Internet. • In the "Network" configuration window in Windows 95, there is no option for NetBIOS over TCP/IP, but a "NetBEUI" entry, with which Microsoft actually means NetBIOS over NetBEUI. • With the installation of TCP/IP protocol, Windows automatically installs the "NetBIOS over TCP/IP”. • If you do want the TCP/IP protocol, but not "NetBIOS over TCP/IP" (because of security problem), you should uncheck "Files and Printer Sharing" in the Bindings tab of the TCP/IP entry in Network Configuration.