TCP/IP- Related Problems
Problem Source Common Characteristics
Configuration -: The host will not initialize or one of the service will not start
IP addressing - : you will not be able to communicate with other hosts.The host could hang.
Subnetting - :you can ping your workstation, but may not be
Address resolution-: you
can ping your workstation, but not other hosts.
NetBIOS name resolution -: you
can access a host by its IP address, but not establish
a connection with a net Command.
Host name resolution-: you access a host by its IP address, but not by its host Name.
Use this tool: TO:
PING - : Verify that TCP/IP is configured correctly and that Another host is available.
ARP -: View
the ARP cache to detect invalid entries.
NETSTAT -: Display protocol statistics and the current state TCP/IP connections.
IPCONFIG -: Verify TCP/IP configuration, including DHCP and WINS Server addresses.
TRACERT -: Verify the route to a remote host.
ROUTE -: Display
or modify the local routing table.
NSLOOKUP -: Display
information from DNS name servers.
Microsoft SNMP service -: Supply statistical information to SNMP management Systems.
Event log-: Track errors and events.
Performance Monitor -: Analyze performance and detect bottlenecks.
Network Monitor-: Capture incoming and outgoing packets to analyze a Problem.
TCP/IP Utilities
Data transfer utility function
File
transfer protocol (FTP) -: Provide
bi-directional file transfers between two TCP/IP hosts,
where one is running FTP server software.
Trivial file
transfer protocol (RCP) -: provides
bi directional file transfer between two TCP/IP hosts,
where one is running TFTP server software.
Remote copy
protocol (RCP) copies
file between a Windows NT based computer and a UNIX®
host.
Telnet -: provide
terminal emulation to a TCP/IP host running Telnet
server software.
Remote shell
(RSH)-: Runs
commands on a UNIX host.
Remote execution (REXEC) -: Runs a process on a remote computer.
Printing utility function
Line printer
remote (LPR) -: Prints
a file to a host running the line printing Daemon (LPD) service.
Line printer
queue (LPQ) -: Obtains
status of a print queue on a host running the line printing
daemon (LPD) service.
Line printing daemon (LPD) -: service LPR requests and submits print jobs to a printer device.
Diagnostics
utility function
Packet internet
groper (PING) -: Verifies
that TCP/IP is configured correctly and that another
host is available.
IPCONFIG -: Verifies
TCP/IP configuration, including Dynamic Host Configuration
protocol (DHCP), DNS, and WINS server address.
Finger -: Retrieves
system information from a remote computer
That
supports the TCP/IP finger service.
NSLOOKUP -: Examines
entries in the domain name system (DNS) database
that pertain to a particular host or domain.
HOSTNAME-: Returns
the local computer’s host name for authentication.
NETSTAT -: Displays protocol statistics and the current state of TCP/IP Connections.
NBTSTAT-: Checks
the state of current NetBIOS over TCP/IP connections,
updates the LMHOSTS cache, or determines your
registered name and scope ID.
ROUTE-: Views
or modifies the local routing table.
TRACERT -:Verifies
the route used from the local host a remote host.
Address
Resolution protocol (ARP) -: Displays
a cache of locally resolved IP addresses to media Access
Control (MAC) address.
NETWORK
SECURITY
REQUIREMENTSWith the introduction of the computer, the need for automated tools for protecting files and other information stored on the computer became evident. The generic name of the collection of tools designed to protect data and to thwart hackers is computer security.
The second major change that affected security is the introduction of
distributed systems and the used of networks and communications facilities for
carrying data between terminal user and computer and between computer and
computer. Network security measures are needed to protect data during their
transmission and to guarantee that data transmissions are authentic. Computer
and network security address three requirements :—
v Confidentiality :
Requires that data only be accessible
for reading by authorized parties. This type of access includes printing,
displaying, and other forms of disclosure, including simply revealing the
existence of an object.
v Integrity :
Requires that data can be modified only by
authorized parties. Modification includes writing, changing, changing status,
deleting, and creating.
v Availability :
Requires
that data are available to authorized parties. .A useful categorization of
attacks on network security is in terms of passive attacks and active attacks.
v Passive Attacks :
Passive attacks are in the nature of
eavesdropping on, or
monitoring of, transmissions. The goal of the opponent is to obtain information
that is being transmitted. Two types of passive attacks are release of message
contents and traffic analysis. Passive attacks are very difficult to detect
because they do not involve any alteration of the data. However, it is feasible
to prevent the success of these attacks. Thus, the emphasis in dealing with
passive attacks is on prevention rather than detection.
v Active Attacks :
Active attacks involve some modification of the data stream or the
creation of a false stream and can be subdivided into categories: masquerade,
replay, modification of messages, and denial of service.
Active attacks present the opposite
characteristics of passive attacks. Whereas passive attacks are difficult to
detect, measures are available to prevent their success. On the other hand, it
is quite difficult to prevent active attacks absolutely, because to do so would
require physical protection of all communications facilities and paths at all
times. Instead, the goal is to detect them and to recover from any disruption
or delays caused by them. Because the detection has a deterrent effect, it may
also contribute to prevention.
Translation results
आवश्यक है कि डेटा केवल अधिकृत पक्षों द्वारा पढ़ने के लिए सुलभ हो। इस प्रकार की पहुंच में किसी वस्तु के अस्तित्व को प्रकट करने सहित मुद्रण, प्रदर्शित करना और प्रकटीकरण के अन्य रूप शामिल हैं
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