Contents
 Ping

Use ping to determine if a specific host is connected to the network.

Introduction

What Is Ping?

How To...

Determine if a Host is Available

Cancel a Ping Query

Set Ping Options

Troubleshoot Ping Problems


Determine If a Host Is Available

1.	Double-click the Ping icon.

The Ping dialog box opens.

2.	In the Host edit box, enter a host name or an IP address.

3.	Click Ping.

Ping results appear in the output panel of the Ping dialog box.


What Is Ping?

Ping is a tool you can use to see if a particular machine is connected to a network. Ping transmits one or more packets containing ICMP echo requests to the remote host you specify. If the remote host is connected to the network and functioning, the host responds to (echoes) Ping's transmission. You can control the number and format of Ping transmissions by selecting Ping Options.

Ping output includes information about packets, and round trip times, and indicates the quality of the packet exchange. When a remote host does not respond to a Ping request, Ping informs you that the remote host is unavailable.

Use Ping to determine the availability of a remote host if you have difficulty:

Establishing a Telnet session with the remote host.

Connecting a drive to a file system located on the remote host.

Accessing a printer connected to the remote host.


Cancel a Ping Operation

1.	Initiate a Ping query.

The Ping button label changes to Stop.

2.	Choose Stop.

The Ping query is halted.


Ping Options

You set Ping options by entering values or checking boxes. Ping Options include:

Number of Packets - Enter a value between 1 and 9999 to specify how many packets Ping sends to the remote host. The default is 1.

Interval - Enter a value between 1 and 9999 to specify the time duration in seconds between packet transmissions. The default is 1.

Packet Size - Enter a value between 4 and 8056 to specify the size in bytes of transmitted packets.

Packets to send before receiving - Enter a value between 0 and 9999 to specify the number of packets sent before Ping accepts a response.

Don't Route - Check this box to prevent Ping from using routing information contained in your PC's routing table.

Record Route - Check this box to force Ping to record the route used to exchange packets with the remote host. Up to nine hops are recorded.

Flood - Check this box to force Ping to send ICMP echo requests as quickly as possible, without waiting for a response from the remote host.


Set Ping Options

To set Ping options:

1.	Double-click the Ping icon.

The Ping dialog box opens.

2.	Choose Options.

The Ping Options dialog box opens.

3.	Enter values for the options you want to change in the text boxes.

Choose Defaults to restore default options.

4.	Enable or disable the Don't Route, Record Route, and Flood options.

A check appears in the check box of an enabled option.

5.	Choose OK.

Your changes are made for this Ping session.

Alternatively, choose Cancel to close the Ping Options dialog boxwithout making changes.


Ping Output

Two types of statistics are available from Ping: Packet statistics and Round Trip Time statistics.

Packet statistics are:

Sent - The number of packets that have been sent to the selected machine.

Received - The number of packets returned by the selected machine. A returned packet indicates that the machine is successfully responding to network activity.

Loss % - The number of lost packets divided by the number of packets sent. This percentage indicates how reliably the remote host and the network are responding.

Round Trip Time statistics are:

Last - The last round trip time in milliseconds of a packet exchange between your machine and the selected host.

Min - The shortest round trip time in milliseconds of a packet exchange between your machine and the selected host.

Max - The longest round trip time in milliseconds of a packet exchange between your machine and the selected host.

Avg - The average round trip time in milliseconds of a packet exchange between your machine and the selected host.


Record Route

When you enable this option, Ping records the route packets taken from your machine to the machine you are pinging. Use this option to track a packets progress through the network. The first nine hops a packet takes are recorded.


Don't Route

Enable this option to bypass the normal routing tables and send packets directly to a host on an attached network. You can also use this option to ping a local host through an interface that has been dropped by the router daemon.


Flood

Enable this option to force Ping to send ICMP echo requests as fast as possible, without waiting for any response from the remote host. You can use this option to benchmark overall network transmission speed.


Ping

The Ping utility lets you determine if your PC has a working connection to another computer over a network. Ping issues an ICMP echo request to a remote machine. If the remote machine is present, it responds to the request. If no response is received, it is assumed that the remote machine is not reachable on the network.


ICMP Echo Request

A fixed-format message (called a datagram) sent from one machine to another. The datagram elicits a response (echo) from the machine to which it is sent.


Troubleshoot Ping Problems

Here are some common problems you can have when you try to connect your PC to another computer on a network. Click on a problem to view possible solutions.

Problem	Possible Causes
Host Unknown	The name server cannot find an IP address for the remote computer.
Host Unreachable	The remote computer, the network, or part of the network is down.
Host Not Responding	The remote computer or a part of the network is down.


Host Unknown

Your computer cannot find a name for the remote computer in the name service.

Some things you can check:

•	Make sure you typed the correct name for the remote computer.

•	Ping the remote computer's IP address.

If it responds, the computer is working, but its name can't be found.
If the remote computer does not respond, see Host Unreachable for troubleshooting tips.

•	Ping the name server by name and IP address.
If the server does not respond, possible problems are:

⇒	The name server is not working or does not exist.
Ask your network administrator for the name of another name server.

⇒	You have the wrong IP address for the name server in your hosts file.
Check the IP address for the name server with your network administrator.

⇒	The name server is unreachable.
Ask your network administrator for the name of another name server.

•	Make sure the name service has the correct host name and IP address for the remote computer.

For NIS, use the Remote Command dialog box to run this command:

ypcat hosts | grep remotecomputer

If the remote computer name is not listed in the hosts file, ask your network administrator to add its name and IP address to the hosts file, or give you the name of another name server.

For DNS, check with your network administrator.


Host Unreachable

Your computer knows how to find the remote computer, but the network is down.

Some things you can check:

•	Your Personal Computer

•	The Local Area Network (LAN)

•	The Gateway


Your Personal Computer

•	Make sure the network or modem cables on your computer are tight.

•	Ping your computer from another computer on the same network.  If your computer responds, you know that your local interface is working.

•	If you are not using DHCP, check these TCP/IP configuration settings with your network administrator:

⇒	Your computer name and IP address

⇒	Your subnet mask

•	If your configuration settings are correct, try exiting windows and turning off your computer. Turn the computer back on.  Rebooting the machine in this way can sometimes clear memory and solve the problem.


The Local Area Network (LAN)

•	Ping another computer on the same subnetwork (one that is close to yours) to make sure the local network is working

•	If you can ping your name server but not your gateway, the gateway is down or incorrectly configured  You cannot reach anyone outside your local network.

•	If you can ping your gateway, either the remote computer is down or the gateway cannot find a route to the remote computer.


The Gateway

If the remote computer is not on the same subnetwork as your computer, your computer sends messages to the remote computer through a gateway.

•	Check the routing on your computer.  Select Network Statistics  Routing Option and click Display.  The gateway host listed next to Default should be noted as U (Up) and G (Gateway).  If the gateway is not up or is not configured as a gateway, ask your network administrator for the name of a properly configured gateway system.

•	Ask your network administrator to make sure the routing tables on the gateway contain an entry for the remote computers network.


Host Not Responding

Your computer sent a message to the remote computer.  But, the remote computer did not respond.

•	Make sure the network or modem cables on your computer are tight.

•	Try to ping the computer again in about 10 minutes.

•	Contact your network administrator.


Name Server

A name server is a machine that looks up the names of other machines on the network.


Gateway

A gateway is a machine that provides a route between two networks.


Route

The path network traffic takes through a gateway to get to networks other than the local network.


Name Service

A service that provides the IP address or name of a computer that is listed in the name service database (for example, NIS, DNS, and local hosts files).


Subnet Mask

A 32-bit address mask that identifies which bits of an IP address represent network address information and which bits represent host information for an IP subnet.


Subnetwork

A means of making the Ethernet address for small networks more efficient by splitting host numbers into two fields.  A subnet address is an extension of the Internet addressing scheme that enables a site to use a single Internet address for multiple physical networks.