These are the online networking tools that would be useful for troubleshooting network problems:
http://www.all-nettools.com/tools1.htm;http://www.samspade.org/;http://us.mirror.menandmice.com/cgi-bin/DoDig;http://www.checkdns.org/;http://www.simplelogic.com/net_utils/;http://www.blackcode.com/net-tools/;http://www.network-tools.com/;http://www.antionline.com/tools-and-toys/
And to check for open relay mail servers, you can check for these sites;
http://www.ordb.org/;http://www.mail-abuse.org;http://www.dsbl.org
I'll just update my blogger for other tools ;

My schoolmate then asked me several questions about Windows, you can check this site www.tiplord.com
tip 1: thnx to @dik for this tip (enabling cd-rom thru DOS)
[[fOR config.sys]]
device=\himem.sys
device=\oakcdrom.sys /d:mscd001
files=30
buffers=60
[[for autoexec.bat]]
\mscdex.exe
/d:mscd001

here's a telnet server to ping for packet losses outside the network >>route-server.cerf.net

http://www.php.net/distributions/manual/php_manual_en.chm;http://weblabor.hu/php-doc-chm/ << windows chm help file documentation