TCP/IP RELATED PROBLEMS & SOLUTIONS

 

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 able to Access local or remote hosts.

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.

 NETSTAT -: Check the state of current NetBIOS over TCO/IP Connections, update the LMHOSTS     cache, or determine Your registered name and scope ID.                                                                                       

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.

 Registry Editor Browse and edit the configuration parameters.


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.

 Remote execution utility      function

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 resultसमस्या स्रोत

No comments