This tutorial describes the methodical ways and means diagnosis based network stack TCP / IP, used in modern network operating systems. We give concrete, practical examples, characterize the possibility of using diagnostic tools in different situations.
APPROVED by chair of Communication Networks
and recommended to type Protocol number 5 on November 29, 2002
Built ANALYSIS OF CONFIGURATION OF THE NETWORK ON THE BASE OF TCP / IP
1 Purpose of the work
1. Analysis of the built-in network diagnostics based on TCP / IP and getting practical skills of diagnostics.
2 Key statements
2.1 Basic tools used for network diagnostics based on TCP / IP
Internet - the largest and one of its kind network in the world. Among global networks, it occupies a unique position. It correctly regarded as a sub network - the union of many networks, preserving independent significance. Indeed, the Internet has no clearly defined ownership, nor national origin. Any network can be connected to the Internet, and therefore, be considered as part of it, if it uses accepted for Internet protocols TCP / IP (Transmission Control Protocol / Internet Protocol) or is there a converter in the protocols TCP / IP. TCP / IP - an industry standard stack protocols designed for wide area networks. The composition of the family includes protocols UDP, ARP, ICMP, TELNET, FTP and many others. As the manifestation of an unstable individual nodes in the network based on TCP / IP the most important issue is the possibility of its monitoring and analysis. One method of diagnosing networks is the utility (short program) included in of the software package, TCP / IP. The main utilities used in modern operating systems (OS), are:
· Ping - a procedure that is used for testing of the channels and nodes. · Tracert (Traceroute) - displays the addresses of all routers on the way from client to remote host. · Nslookup - check for the correct names in the address conversion and vice versa. · Netstat - displays stats and current connections for the protocol TCP / IP.
· Ipconfig - shows the setup protocol IP. Default displays only IP-address, subnet mask and default gateway for connection each adapter, which is executed for binding to TCP / IP. · Winipcfg - utility similar Ipconfig, but not in working mode command line, and by application interface. It can be use only on Windows 98. · Finger - used to obtain information about the user removed machine. · Telnet - use the Internet standard protocol for obtaining terminal access to remote machines. · Whois - Search the Whois database for registration information net domain name, user's phone number, e-mail address and more. · Net Time - sync system time with master server.
utilities ping and tracert
Utilities ping and tracert (traceroute), used independently or together, determine the path that goes over the network packet to the destination and time, he reaches it. Based on the results of tests ping and tracert, you can determine where it stopped.
Utility Ping by sending messages with echo-request protocol ICMP (Internet Control Message Protocol) connections to examine IP protocol level to another computer that supports TCP / IP. After each transmission of a message is displayed with an echo-response. Team ping, running without parameters displays help.
Syntax ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v type] [-r count] [-S count] [{-j spysok_vuzliv |-k spysok_vuzliv}] [-w interval] [name of the end computer]
Options Setup Utility Ping presented in Table 2.1
Parameter identifier
Purpose
-t
Specifies the ping command to send messages with echo-request to destination for as long as the team will not be interrupted. To interrupt the command and output statistics to click combination of keys CTRL-BREAK. To interrupt the ping command and withdrawal from the need to press CTRL-C
-a
Specifies the hostname resolution on the IP-address assignment. In the case of successful implementation of the name of the output node
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-n counter
Specifies the number of messages with echo-request sent. By Default - 4
-l size
Specifies the length (in bytes) of data fields in the messages they send with echo-request. Default - 32 bytes. Maximum Size - 65 527
-f
Specifies the posting of an echo-request from the flag «Don't Fragment» in IP-header is set to 1. Posts echo-request not fragmentize routers towards the destination. This option useful for troubleshooting problems that arise with the maximum block of data (Maximum Transmission Unit) for Posts with echo-request. Default - 32 bytes. Maximum Size - 65 527
-i
TTL
For messages with echo-request sent, sets field value TTL (Time to Live) in IP-header. Default takes the value TTL, the default node. For example, Windows XP units this value is usually 128. The maximum value of TTL - 255
-v
type
For messages with echo-request sent, sets value type field service (TOS) in the IP-header. A decimal value from 0 to 255. By default, this value is 0
-r
count
Specifies the record route option (Record Route) in the IP-header for entry way which passes messages from the echo-request and an appropriate message from an echo-response. Each transition (Intermediate router) in the way of using parameter routes. If possible, count is set equal to or greater than the number of transitions between source and destination. Option counter has a value from 1 to 9
-s
count
Specifies the time stamp option Internet (Internet Timestamp) in IP header to record the arrival time of messages from the echo- request and appropriate for the message-echo response for each transition. Option counter has a value from 1 to 4
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-j
list of nodes
For messages with echo-request parameter specifies the use of free routing in IP-header with a set of intermediate points purpose specified in the list of nodes. When free routing successive intermediate destination can be divided one or more routers. Maximum addresses or names in the list of nodes - 9. List of knots - a set of IP- addresses (in dotted-decimal notation) separated by spaces
-k
list of nodes
For messages with echo-request parameter specifies the use of strict routing in IP-header with a set of intermediate points purpose specified in the list of nodes. When strict Routing the next intermediate destination policy- available directly (it must be nearby in the interface router). Maximum number of addresses or names in the list nodes is 9. List of knots - a set of IP-addresses (in dotted-decimal notation) separated by spaces
-w
interval
Specifies the waiting time in milliseconds from receipt of the notice echo-reply message with the corresponding echo-request. If a message with an echo-response is not received within given interval, then an error message "Request timed out". The default interval is 4000 (four second)
Name of destination computer
Specifies the destination point identified IP-address or name node
-?
Displays help at the command line
The following example shows the results of the command ping:
C: \> ping-l 1964 www.nnm.ru Ping www.nnm.ru [213.248.7.66] with 64 bytes: Reply from 213.248.7.66: byte = 64 h = 491ms TTL = 44 Reply from 213.248.7.66: byte = 64 h = 711ms TTL = 44 Reply from 213.248.7.66: byte = 64 h = 831ms TTL = 44 Reply from 213.248.7.66: byte = 64 h = 471ms TTL = 44 Ping statistics for 213.248.7.66: Packets: sent = 4 received = 4, Lost = 0 (0% loss), Estimated time of transmission and reception: smallest = 471ms, largest = 831ms, average = 626ms
Tracert utility determines the path to the destination using reference point in Lung-purpose of ICMP messages with a constant increasing values of lifetime (TTL) in the header packet. Derived path - a list of the nearest router that is on the road junction between the source and destination. Closer interface is a router interface that is closest to the sender node way. Launched without parameters, tracert displays help team.
Syntax tracert [-d] [-h maximum number of conversion] [-j list of nodes] [-w interval] [Name of destination computer]
Parameters Options of Tracert utilities are presented in Table 2.2
Parameter identifier
Purpose
-d
Prevents the transformation of IP-address intermediate routers named. Increases the speed of output results tracert command
-h
max number of conversion
Specifies the maximum number of points on the way in finding finite object. The default value is 30
-j list of node
For messages with echo-request parameter specifies the use of free routing in the IP header for a set of intermediate purpose mentioned in the list of nodes. When free routing successful intermediate destinations can be separated by one or more routers. Maximum number of addresses or names on the list - 9. List of nodes represents a set of IP-addresses (in dotted-decimal notation) separated by spaces
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-w
interval
Specifies in milliseconds while waiting to get answers Lung- ICMP protocol or ICMP-messages about the time that has passed, that meet this echo-request message. If message is not received within a specified time, output asterisk (*). Timeout default 4000 (4 seconds)
Name of destination computer
Specifies the destination specified IP-address or host name
-?
Displays help at the command line
Note. Each router through which the path is obliged to further forward the packets to reduce the TTL field value in its header to 1. In fact, TTL - meter units. Assumed that when TTL parameter is 0, the router sends the source systems ICMP message about the time that has passed.
Tracert command determines the route, sending the first echo-request from field TTL, which is 1. Further, this value will increase by unit for each echo packet is sent, as long until the final site will answer or until the Maximum the field TTL. Maximum Conversion Default is 30 and can be changed with the option-h. Way determined from analysis of ICMP messages elapsed time obtained from intermediate routers, and Lung-answer destination. However, some Routers do not send messages about the time that has elapsed for packages zero TTL values and therefore does not see team tracert. In this case for conversion is a series of asterisks (*).
Example: C: \> tracert-h 10 www.aport.ru Tracing route to aport.ru [194.67.18.8] with the maximum number conversion 10:
1120 ms 120 ms 121 ms max3.farlep.net [213.130.1.251] 2130 ms 120 ms 120 ms teller-10mb-gw.farlep.net [213.130.1.254] 3120 ms 120 ms 791 ms core-0-0FE.farlep.net [213.130.0.28] 4141 ms 140 ms 160 ms core-0-pa4T-1-0-201fr.kiev.farlep.[213.130.0.102] 5801 ms 150 ms 150 ms router113.ukrsat.com [212.35.171.113] 6161 ms 150 ms 160 ms cyclone.ukrsat.com [212.35.160.97] 7731 ms 731 ms 751 ms NO-NIT-TN-6.taide.net [193.219.192.6] 8711 ms 711 ms 701 ms NO-NIT-TN-8.taide.net [193.219.193.138] 9711 ms 701 ms 711 ms oso-okr-i1-pos1-1.telia.net [213.248.78.49] 10 701 ms 711 ms 691 ms s-bb1-pos0-0-0.telia.net [213.248.66.89]
Trace complete.
3 KEY QUESTIONS 1.3 List the basic tools built into OS, designed for analysis configuration and state of the network based on TCP / IP. 2.3 Specify the purpose and main parameters of utility ping 3.3 Specify the parameters and the basic utilities tracert. 3.3 What does the command ping 127.0.0.1? 4.3 Specify the purpose utility nslookup. 3.5 For what we need to use utility netstat? 6.3 What outputs utility ipconfig by default? 3.7For what do we use the utility Telnet?
4 Homework 4.1 Investigate, using this guidance, the main built-in facilities intended for the analysis of configuration and status network based on TCP / IP. 2.4 Prepare a protocol of the laboratory work, which reflect the theme purpose of the work, a brief description of utilities designed to analyze configuration and state of the network based on TCP / IP. 4.3 Prepare answers to key questions
Laboratory task
5.1 Objective 1. Using ping and tracert tools for analysis configuration and state of the network based on TCP / IP
1. Using a utility ping, check the connection with the following Nodes: www.infoart.ru, www.mari.ru, www.rambler.ru, www.marsu.ru, www.altavista.com, www.nn.onat.ira.net. Decide to nodes which can be accessed and by whom - no. Define time access to specified sites. 2. Follow the ping utility with the addresses to which access was obtained in Clause 1 of the keys. 3. Using a utility tracert, define routes to hosts, to which was obtained access to item 1. For each analyzed route record the total number of routers and their IP- addresses and domain names. 4. Do a tracert utility keys. Note. To open a command prompt, press Start button and select All Programs, Standards and command lines.
