These commands are considered general because they
can be applied on end-systems running the most common operating
systems. Figure shows commands that a troubleshooter uses on an
end-system running a Windows operating system to gather
information about the network configuration of an end-system.
Figure shows commands that a troubleshooter uses on an
end-system running the UNIX or Mac OS X operating systems to
gather information about the network configuration of an
end-system.
Content 1.3 Building-Block
Approach 1.3.4 Discovering end-system
configuration information The following steps outline the
procedure for discovering the network configuration of an
end-system. Step 1
View information about the
operating system and hardware of the device. Note: On a
Windows end-system, information about the operating system and
hardware can be accessed by choosing
Start>Settings>Control Panel and
then double-click the Systems icon. On a Mac running Mac
OS X, click the Apple icon and choose About This Mac. Step
2
Access a command line. Note: To access a
command line on a Windows end-system, choose MS-DOS or
Command Prompt from the Start Menu. The command line
Terminal utility on Mac OS X can be found in the Utilities
folder located in the Applications directory. Step 3
View detailed information about the TCP/IP settings of a
device. This is accomplished by entering the ipconfig
/all or winipcfg commands in a Windows command
prompt or entering ifconfig -a in a UNIX or Mac OS X
command line. The important information to record includes the
following: IP address/subnet mask, default gateway address, and
any DNS or WINS server addresses. When viewing the information
returned from ipconfig /all, it is helpful to note if
the IP address of a device is static or if it has been
temporarily assigned through DHCP. Step 4
Display
any active routes by entering the route print command
in the command line. Step 5
View Address Resolution
Protocol (ARP) information by entering the arp -a
command. Step 6
Check connectivity to remote
devices by attempting to ping a device across a link.
Step 7
View the route that is used to connect to a
remote address such as the default gateway. To accomplish this,
enter tracert {ip-address | hostname} in
a Windows command prompt or enter traceroute
{ip-address | hostname} on a UNIX or Mac OS X
command line. Step 8
Check that TCP is available
and functioning on the end-system by entering the telnet
{ip-address | hostname} command.
Content 1.3 Building-Block Approach
1.3.5 Creating end-system network configuration
documentation Good end-system network configuration
documentation allows rapid discovery of specific information
about end-systems. Guidelines for creating effective end-system
network configuration documentation are: - Know which
end systems are part of the domain to determine the scope of
the end-system network documentation.
- Only collect
data that is relevant to the objective and provide sufficient
detail for those relative pieces. Extra layers of information
will only make the documentation more difficult to use.
- Use consistent terminology, abbreviations, and style.
- Try to make the documents orderly and easy to
understand.
- Use templates and keep a library of
symbols and graphic icons.
- Store the network
documentation in a location where it is readily available on
the job. A copy of the documentation should be kept in a secure
location off-site.
- Maintain the documentation!
- Modify the network documentation as conditions and devices
in the network change.
A process should be
implemented for handling changes to the network documentation.
Factors in this process that need to be accounted for are
reporting network changes, maintaining version control, and
assigning responsibility for modifying and distributing updated
documents. Example
A network technician’s primary
job function may be to maintain and troubleshoot network
servers and desktops. The team already does a respectable job
of fixing problems but has been asked to create documentation
of the network end-systems to expedite troubleshooting efforts
and cut down on costs. The company currently has configuration
tables and topology diagrams of the network configuration
without end-systems. A month later, the network support staff
has been using the end-system documentation for
troubleshooting. Estimates have determined that the time that
the department spends troubleshooting end-systems in the past
month has dropped considerably. The documentation was a success
for the following reasons: - The scope of the
documentation was determined accurately because of familiarity
with the end-systems on the network.
- The appropriate
types and amounts of information for each documented end-system
were recorded.
- Standardized symbols and terminology
consistent with the existing network documentation were used.
- Documentation was kept current by implementing a
system for employees to report changes and by updating the
documentation in a timely manner.
- The documentation
was stored in convenient and clearly marked locations close to
each administrative terminal.
Lab Activity
Lab Exercise: End-System Baseline discovery In this lab, the
student will establish the baseline for the configuration and
operation of the end-systems in the student network.
Content Summary In this module, it was explained that a
network baseline is required for effective troubleshooting.
Devices and key interfaces should be baselined to provide a
reference for subsequent analysis. The thresholds for these
devices and interfaces should be documented. The need for
network documentation consisting of a network configuration
table and topology diagram was emphasized. The components of a
network configuration table and topology diagram can be
categorized by the logical layers that they are associated with
in the TCP/IP model. Following established procedures, a
troubleshooter can gather relevant configuration information
about routers and switches. Performing the five stages in the
process of creating network documentation allows a
troubleshooter to create a network configuration table and
topology diagram. Following guidelines makes it easy for a
troubleshooter to create useful and effective network
configuration documentation. End-system documentation consists
of a configuration table and end-to-end topology diagram. The
components of an end-system configuration table and topology
diagram can be split into physical and logical categories.
Following established procedures, a troubleshooter can gather
relevant configuration information about a variety of
end-systems. There are several commands and applications
available for discovering configuration information about
end-systems. Good end-system configuration documentation allows
rapid discovery of specific information about end-systems. The
next module will expand on internetwork troubleshooting with an
exploration of troubleshooting methodologies and tools.