Homework 3.2 Clients Hub What’s wrong with this picture? Clients Using 100TX

Client and Server Systems Operating Systems –Windows 95/98 –Windows NT Workstation –Windows NT Server Centralized Security and system policies Telecommunications –Fax, mail, web

Network Servers Network Operating Systems –Timesharing: splitting time between jobs –Multitasking: processing more that one job at a time –Parallel Processing: more than one cpu processing jobs –Load Balancing: sending jobs to different servers

Multitasking Preemptive –OS can take over a task without cooperation of the task. Nonpreemptive –The task decides if it will give up the processor.

Dedicated vs. Nondedicated Dedicated Server –Server does server tasks only, it does not execute local programs (Novell) –CPU time is dedicated to server operations Non Dedicated Server –The user has an interface to the OS on the server and can execute programs locally (Linux, Microsoft)

Software Components Client –File access, Printing, Database access Server –Disks, Printers, Programs Redirectors –Handles client requests Forwards a local request to LPT1: to print server Accesses non local drive letters: F:\>, G:\>, etc

Server Software Resource Sharing –File access: remote access to servers disks –Printer access: remote requests to local printer –Security and control Which users can access the disk or printer? Which users can write to the disk? File locking when 2 users want to write to the same file. Account for disk usage and printer paper

Server Administration Managing Users –Privileges Access to resources Passwords –Location of users (address, , etc.) –Time limits (8:00 AM to 5:00 PM) –Station limits (specific MAC address) Resource load balancing

Novell Operating Systems NetWare –NDS (Novell Directory Services) Disk caching and distribution among servers –NDPS (Novell Distributed Printing Services) –Web Servers –Mail Services –Calendaring/Scheduling –Messenger service –Routing

Novell File Services Logon Security –Authentication Trustee Rights –Who can access what file/directory and what can they do with the file Directory attributes –The types of operations on a file (read, write, shareable, copyable)

Novell Distributed Printing Services Print spooling and control –Access by users to specific printers –Print load is transferred from client to server –Printer messages (out of paper, change form) are displayed on the server console. –Server handles multivendor printing protocols so client doesn’t need to. –Clients can share their printer through the server

Microsoft Network Operating Systems Windows NT (includes Win2000, XP) –Single domain, single server, small workgroup –Single master, single server, multiple workgroups –Multiple master, multiple servers, several workgroups, accounts on multiple servers –Complete Trust Several domains no master (workgroups trust each other)

Windows NT Services File services –Similar to Novell, access, control, rights –Security, server maintains access lists Printing –Clients or servers can share their local printers Routing and Remote access Other services –Messenger, Alerter, Browser

Interoperability Gateway Services for NetWare –Handles NetWare requests for a domain Client Services for NetWare –Handles NetWare requests for a workstation File and Print Services for NetWare –Protocol converter Directory Service Manager for NetWare –Allows Windows clients to access NDS Services for Macintosh –Allows Appletalk service on the NT server

Appletalk Networks Appleshare –Apple disk and printer sharing (Apple has it’s own file formats) –Zones (Apple’s workgroups/domains) –Security (each client maintains it’s own lists) –Appletalk servers can handle multiple protocols (TCP/IP, Appletalk, Microsoft)

UNIX (and Linux) Networks Simple Client only to Server transformation Can handle multiple protocols and services (Apple, Microsoft SMB, NFS) Can be configured as a router/firewall Well adapted to remote access

Peer to Peer Simple to set up (almost all OS’s have built in peer to peer support) Access lists are kept on each computer, there is no master server. Useful for small (10 or less) workstations Somewhat insecure

Interoperability Multivendor environments –Servers can support different OS clients –Files transferred from different server types go through the client –Files transferred from different client OS’s go through the server –File formats may be different on each vendors operating system. File type conversion can be done on the server or client. –Authentication is almost always different between vendors. –Network Protocols may also be different between vendors

Server Security Warnings: –When a server is placed on the network it is now wide open for attack. –All Network Operating Systems have bugs and security holes. –Always upgrade to the latest revisions of the OS –Limit the number of services provided by the server to the minimum needed for your particular application –Use firewalls as needed in the local area network

Network Types What Protocol to use? –IPX –TCP/IP –Netbeui Which Name Service? –DNS –WINS –LMHOSTS

Windows NT/95/98/2K Client Pick a name (15 characters NetBios limit) –Or use WINS Pick a workgroup or domain Get networking working Add appropriate protocols Edit LMHOSTS (for TCP/IP) Use Network Neighborhood or Find Computer to find the server

Workgroup/Domain Workgroup –Login is on each client –Simple, minimal security –No dedicated server Domain –Login is to the server over the network –Requires an NT Domain Server –High security, centralized usernames/passwords

Accessing Server Resources Nbtstat to check netbios connectivity UNC –universal naming convention –\\ntserver\users –\\ntserver\laser_office net use –net use j: \\opie\bobw –net use lpt1: \\ntserver\laser_office

Web Services Web Server (IIS on NT based systems) Security Issues –File access –Database access –CGI programs Counters Data Entry

Mail Services SMTP Support POP and IMAP mail support Novell Groupwise –Calendaring –Scheduling Microsoft Exchange –Calendaring –Scheduling

Other Services DATABASE Support –Microsoft SQL Support –Oracle Support –MySQL Support Distributed License Service Accounting of server and resource use –Disk space –Pages printed