Ping - Input:  IP address or host name
Sends signals (packets) to another computer on the Internet to see if they send a return or an 'echo.'  If all the signals 'timeout' the computer may be disconnected from the Internet or at least unreachable from the server.  This feature only checks a computer connected to the Internet, it cannot verify the validity of an e-mail address.  It also cannot check a specific web page, but you can check the main server to see if it is connected ( is valid but is not).

Lookup - Input:  IP address or host name.  
If an IP address is input this converts into a computer host name.  It will also do the reverse process if a computer name is entered.  This function has nothing to do with looking up e-mail addresses.

A computer name may or may not be 'fully qualified domain name.'  This means that the computer is part of Internet registration system and the name can be converted both ways.  Example: converts to  It is also possible to give the computer a non-registered name such as 'JOE.'  In this case the result of a lookup on the IP address would be 'JOE' but a lookup on 'Joe' will not give the IP address.  This feature only looks up IP addresses or computer name, it will not look up e-mail addresses or web pages.

Trace - Input:  IP address or host name  
Traces the route through the Internet from to the destination computer.  The signal generally goes from a computer to the Internet Service Provider (ISP) and then to their provider until it reaches a 'backbone' provider.  This could take one or many steps.  It then eventually transfers to the destination 'backbone' provider and reverses the process to the destination computer.  This feature only checks a computer connected to the Internet, it cannot verify the validity of an e-mail address.  It also cannot check a specific web page ( is valid but is not).  Note that a traceroute may follow a completely different path as compared to downloading web pages or sending e-mail.

XWhois - Input: domain name.  
Program checks domain name and searches for the registration records for that domain based on the top level domain (.com, .uk. .au, etc.).  To find information on a top level domain enter the domain ending such as "com" "uk" "ro" "biz" etc.  This tool cannot look up who owns an e-mail address, just who registered a domain name.

DNS Records - Input: domain name.  
Active domains have a configuration file stored in their nameservers.  This file gives information about what IP addresses are mapped to computer names.  Example: converts to  It also provides information about which mail server a domain uses (Mail eXchanger or MX record).  Example: used the mail server.  
A graphical explanation of how DNS works.  You can determine that a domain name uses a specific mail server but you cannot determine any additional information about an e-mail address.   The administrator of the mail server would have that information.

Network Lookup - Input:  IP address
This automates a network lookup by doing a lookup on the IP address network.  IP address blocks are register by ARIN in the Americas, RIPE in Europe, and APNIC in Asia-Pacific.  A database of IP ownership is maintained.

Express Trace - Input:  IP address or host name
Does a Lookup, Trace, Xwhois, and Network Lookup.  Convenient for checking the origins of junk e-mail.  Input the IP address found in the full headers Example:  [].

URL (Un)Encode - Input: Text string
URL's can be displayed in standard text or "URL Encoded" text.   This text converts several characters to a special code.   For instance "/" is encoded as "%2F".  Junk e-mailers sometimes use this in an attempt to confuse users.  To trace a URL of this type input the string and check the "URL UnEncode" button.  This will convert the string to regular text.   You may need to edit the string to extract just the web site name (like   If the URL contains "@" ignore everything to the left.  http:[email protected]/   is the same as   In this case you would re-enter just

http://network%2Dtools%2Ecom%2Fhelp%2F | will take you to the same web page.

HTTP Headers - Input: web page URL.
(no http://, it is included automatically).  This displays the header of a web page.  This is information passed with with a web page that is not normally displayed by a standard browser.  Depending of the type of web server being contacted, the information could include the type of web server software being used and information about the web page or graphic being accessed.  This could include such things as file size, file creation date, error messages, etc.  To see the headers sent by your web browser click here.

E-mail Validation - Input: E-mail address
This can detect bad e-mail addresses.  It checks syntax, checks if the domain is configured to accept e-mail, and then checks the e-mail server.  Passing this test does not ensure an e-mail address exists but it can be used to detect bad addresses in many cases.  

Convert Base 10 to IP - IP addresses can be converted to a "base 10" number.  Spammers often use this in URL's.  Example:  http://123456789/.  If you wish to trace a URL like this just input the number "123456789" and check the "Base 10" button.   It will convert the number to a standard IP addresses.  If the URL contains "@" ignore everything to the left.  http:[email protected]/ is the same as http://123456789/

A standard IP is "base 256."   To convert to base 10 the formula is:

66 x (256)3 + 46 x (256)2 + 55 x (256)1 + 116 = 1110325108  | | http://1110325108 are identical.

DNS Server - Choose the DNS server to use for the DNS lookup function.  This can be used to query a specific nameserver.  This is convenient to see if each of your nameservers has the proper configuration for the domain entered.   This setting does not affect the DNS server used by the Lookup and Traceroute functions.

Computer ('host') name or domain name? Normally, A domain name is not necessarily a 'host' name. For instance and could be two different 'host' computers under the same domain.   The computers could be separated and result in a completely different traceroute for each.  A domain name, such as ',' may or may not be a 'host' or machine name depending on the configuration.  'Third level' or higher names, such as are not registered except internally to the entity that owns the domain name. Home