Networking in Windows 2000

NT Layered Network Architecture Network Interface Card Network Adapter Card Drivers NDIS InterfaceStreams Transport Protocols Transport Driver Interface NetBIOS driver RedirectorsServers WinSock driver 1. Physical 2. Data Link 3. Network MAC LLC 4. Transport 5. Session 6. Presentation 7. Application Kernel Mode User Mode

Some basic concepts NDIS Interface: Network Driver Specification Interface, wraps NIC drivers and allow communication with multiple protocols, binds a NIC to a protocol. Streams: multiple channels allowing broader bandwidth for data transfer, envelop the protocols. Transport Driver Interface : allows software drivers (server, redirector, etc) to communicate with protocols. Redirectors: software in WS that redirect network drives, printers requests to network I/O requests. Servers: software that allows a device to accept requests from other devices.

Standard NT protocols NetBEUI - NetBIOS Extended User Interface, “native” Windows protocol, not routable. TCP/IP - implemented through WinSock, routable, supports SNMP, DHCP, WINS. NWLink (IPX/SPX) - used to connect to Novell NetWare, just a protocol, not access. DLC - Data Link Control, used to connect to IBM mainframes and HP printers directly connected to a network (server).

Network Resource Access UNC - Universal Naming Convention machine name: \\mname <= 15 digits share name: \sname <= 12 digits example: \\AL200\HP6 sharing: net share public= c:\temp using: net use lpt2: \\Al200\public also graphical Master Browsers - allow to see what resources are available Win NT/2000 use Network Neighborhood MUP driver - Multiple Universal Naming Convention Provider

Workgroup and Domain Peer to Peer a machine joins a group by declaring (Control Panel) group names <= 15 digits peer-to-peer and guest, should not be allowed shares require username and password Concept: a group of NT/2000 machines that share “a security server” - the domain controller Windows 9x may join by selecting as workgroup the domain name user name <= 20 digits, password <= 14 digits users have permissions and rights in groups SAM - Security Account Manager, keep user information Naming a machine and joining a domain: right-click on MyComputer, select properties, Network identification and properties.properties

Addresses Ethernet address (MAC address ) 48-bit unique addresses hard wired in NICs (280 trillion) 12 hex numbers, e.g. 00-A0-C9-9F first three identify company, Intel in the example how to see: System Information, Network Adapter Network Adapter IP address (number) 32-bit value, not hard coded (4 billion), assigned manually or by DHCP four dotted quads, each quad a decimal from 0-255, corresponding to eight bits, e.g. UBMAIL IP address is

Interneting Station A wants to send message to station D, but IP number is not in the same subnet -- no can do! Sends the message to the default IP router -- default gateway All stations belonging to the same subnet share the first three dotted quads and are in the same subnet, while is not.

A,B and C-Class Networks A-class networks first 8 bits fixed, from (only 127) very large companies like IBM, BBN, DEC,HP can assign 3 dotted quads - up to 16.7 million hosts B-class networks first 16 bits fixed, first quad and second (16,384) Medium-sized companies like Microsoft, Exxon can assign 2 dotted quads - up to 65,536 hosts C-class networks first 24 bits fixed, first quad , second and third (2,097,152) can assign 1 dotted quad - up to 253 hosts, 0 is the subnet address., 1 default router address, 255 broadcast address.

Sockets and WinSock Special addresses Network address: first address in subnet (0) Router address: second address in subnet (1) Broadcast address: last address in subnet (255) Sockets are the basic TCP requirement Socket address IP address of the receiver Port number of the receiving program (80,21,23) Type of port TCP or UDP WinSock is an adaptation of sockets to the PC part of the OS (Windows, Linux, etc.) an application programming interface

Setting static IP addresses Go to Control Panel and select Network and Dial- up connections In the first time select Make New Connection, local area network. After the first time right-click on Local Area Connection and select properties. In both cases you will see the properties dialog, which allows you to install/uninstall client, service or protocol.properties Select the Internet Protocol and click on properties Fill in IP number, Subnet Mask, Default Gateway, DNS Fill in Use ping to test your setup. Dynamic IP addresses: use DHCP (Dynamic Host Configuration Protocol), which requires a server in another machine.

How does DHCP work? DHCP CLIENT DHCP CLIENT DHCP SERVER DHCP DATABASE MAC address MAC address, IP#, lease time DHCP discover DHCP offer IP#, lease time IP scope DHCP request IP#, MAC address IP#, lease time DHCP ack (1) (2) (0) Scope - a range of IP addresses IP lease - the IP# is assigned temporarily Reserved IP - servers are assigned fixed IP addresses