You can also use http://scan.sygatetech.com for this purpose. Sygatetech gives a wider range of scan possibilities, it check's more ports and it gives more detailed explanation of theOriginally posted by Rewandythal
4) go to www.grc.com and scan for open ports to check that your firewall is working
ports.
Make sure your firewall not only report attempts but also drops them.
If you mail to the ISP of the intruder with the prove (logs) included, they will take action: they send the intruder some e-mail warning, most times this is sufficient to stop him/her.
You can lookup the intruder IP and ISP with the WHOIS and RIPE databases on the net.
On IRC use /mode yournick +x to hide your IP