Gathering End System Symptoms

This section presents a process you can use to gather symptoms from end systems. Figure 5-2 displays this process with a flowchart. The process starts with interviewing the user and then calls for analyzing, determining, and documenting the symptoms. Finally, you correct the problem if it is possible.

NOTE This book focuses on troubleshooting network connectivity. You might need to seek help from external vendors or workstation and server administrators to effectively troubleshoot problems at end systems.

Figure 5-2 The Process of Gathering Symptoms from an End System

Figure 5-2 The Process of Gathering Symptoms from an End System

The stages of gathering end system symptoms are as follows:

■ Stage 1: Interview User—At Stage 1, if possible, you gather initial symptoms from the user and use these symptoms as a platform to gather symptoms at the end system later.

■ Stage 2: Analyze Symptoms—In Stage 2, you form a description of the problem by analyzing any gathered symptoms from the user.

■ Stage 3: Determine Symptoms—During Stage 3, you gather hardware and software symptoms from the end system using a layered troubleshooting approach, starting with the most likely culprit. You must rely on experience to decide whether the problem is more likely a hardware or a software problem. Starting with the most obvious symptom—gathering symptoms and facts about hardware that is perceived to be malfunctioning—is effective if you physically inspect the suspected devices. Information you gather from the user helps determine the most obvious places to begin. When you are gathering symptoms for perceived software problems, you should test the network applications on the end system. Information you gather from the user helps determine the most obvious applications to test.

■ Stage 4: Document Symptoms—In Stage 4, you document all the hardware and software symptoms. If you can solve the problem using the documented symptoms, you must do so and document the solution. If you cannot solve the problem at this point, you must then begin the Isolating phase of the general troubleshooting process. Table 5-3 lists and describes the commands used to gather symptoms on end systems.

Table 5-3 Commands for Gathering Symptoms on End Systems

Command

Description

ping {host | ip-address}

Sends an echo request packet to the target system and then waits for a reply. The {host | ip-address} variable is the IP alias or IP address of the target system.

telnet {host | ip-address}

Connect to an IP address or host name using the Telnet application.

Windows: tracert [destination] Mac/UNIX: traceroute [destination]

Identifies the path that a packet takes through the network. The [destination] variable is the host name or IP address of the target system.

Windows: ipconfig /all Mac/UNIX: ifconfig -a

Displays information relating to the IP configuration of an end system.

arp -a

Displays the contents of the entire ARP table (local mappings of MAC addresses to their corresponding IP addresses).

route print

Displays the contents of the entire IP routing table (on the end device).

[-n] [-p proto] [-r] [-s]

Displays protocol statistics and current TCP/IP network connections:

-a Displays all connections and listening ports.

-e Displays Ethernet statistics.

-n Displays addresses and port numbers in numerical form.

-p proto Shows connections for the protocol specified by proto; proto can be TCP or UDP.

-r Displays the routing table.

-s Displays per-protocol statistics. By default, statistics are shown for TCP, UDP, and IP; you can use the -p option to specify a subset of the default.

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