Chapter 16. Tools

Table of Contents

Ping
Output
Non-Continuous
Continuous
TraceRoute
Network Scanner
SNMP Browser
DNS Query

The following tools can be accessed through the 'Tools' item on the menu bar, or through the Tools Toolbar.

Ping

When a device is pinged a small fragment of data is sent to the device. The device in turn sends the data back. Almost all IP based devices will respond to a ping. The amount of time taken for the reply from the request to be received back by the sender is called the RTT (Round Trip Time). This is an indication that the device is functioning and the connectivity from the computer doing the request to that of the device answering the request is functioning. There can be reasons other than device failure or connectivity failure for a reply from a ping not to be received, the most common of these would be a firewall of some type in place between the requesting computer and the device being pinged.

On the Ping window there is a button labeled 'Show Adv' or 'Hide Adv'. This button will show or hide the advanced settings for pinging. Once an advanced option has been set, it will be stored and always re-used unless edited.

Table 16.1. Advanced Ping Properties

DelayThe amount of time waited between each ping request sent. The RTT is usually shown in three values, the Average, the Max and the Min. If only one request is sent then the Average, Max and Min will all be the same, so as a general rule more than one ping is sent so a better idea of the effective RTT is calculated over a short period on time, and not only at one instance in time. The number of requests that will be sent on a non-continuous ping is set by the 'Attempts' option. The Delay is the amount of time between each ping request.
TimeoutHow long to wait, in seconds, before assuming the request has failed.
TTL (Time to Live)As the pocket of data sent along the networks goes through a router, the TTL value contained within the pocket is reduced by one every time. Once the TTL reaches zero the router will no longer attempt to forward the pocket on to its destination, but rather abort the attempt and reply to the sender saying TTL expired. If not for the TTL feature in TCP pockets, then a ping request on a bad network could bounce around a network forever.
TOS (Type of Service)This defines a flag within the pocket specifying the type of service of the pocket.
Request SizeThis is the size of the pocket of data sent.
FragmentWhether or not to allow the pocket to be broken up along the way to its destination.
AttemptsThe number of pockets sent in a non-continuous ping.
ContinuousA continuous ping will ignore the Attempts parameter and continually send the ping request at the interval specified by the Delay. This can be useful in locating intermittent network problems, as it allows for a ping test to be performed over an extended period of time.

Output

The output differs depending on whether the ping is continuous or not.

Non-Continuous

The host name, IP Address, Average RTT, Max RTT, Min RTT, Number pockets sent, Number received, Percentage received, TTL and Error are shown on the first 'root' output. This output is general to all ping requests and not just a single request. Beneath that the result of each request is shown. If 3 Attempts were specified there should be three 'child responses'.

Continuous

The output is the same as for the Non-Continuous except that the 'child' outputs are not shown. So a continuous ping will only have one line of output. A continuous ping will not stop until the Ping window is closed or the ping is requested to stop. This is done by right clicking on the host of the continuous ping and selecting the stop item from the popup menu bar.

Also See: the section called “Internal Shortcuts (Ping, Trace Route, SNMP Browse)”


Copyright (c) Warren Flemmer 2006www.net-probe.com