Youve rocked up to work ready to start the day and get on with the list of jobs the boss has graciously gifted you with, when your daily routing of reviewing the logs brings the normal sigh as x.x.x.x is externally scanning and probing for open ports on the perimeter.
Depending on the security stance or care factor the offending IP address may go in a block list, be ignored, be investigated further or none of the above. Lets say that you want to report this so you do a quick WHOIS lookup on the offending IP address. There are plenty of web sites that offer WHOIS lookups but if you want to perform searches from the command line Swa Frantzens guide  is a great refresher.
This is where you can run in to a very frustrating road block of the Useless Contact Email Details. The two worst offenders are the fake email addresses ([email protected]
being a favourite) or the horribly out of date email address of that goes deep into cyber space never to be seen again. One of the fun parts about being on the defensive team is trying to work out if its worthwhile telling someone their computers arent playing nice any more. So make it easy for them to do that and if someone makes that effort, be a good internet citizen and have a valid, current email address on the WHOIS record.
NOTE Before the screaming and tearing of hair occurs because Im advocating putting a valid email address that can be use be the evil smurfs gain information on you or the company, feel free to use on of the numerous WHOIS protection services that shields your email behind one of their email addresses. As long as the email gets to you, thats all that matters.
Fixing WHOIS record details is easy and straightforward*, so get it done and tick off that New Years resolution to help out the internet.
Oh, and should you get a call from someone notifying that something might be wrong with your systems, fellow handler Tom Liston came up with a fairly comprehensive list on how not to response to someone giving you the heads up .
* Unless you work for a big, very big company, so get raised a work ticket and have some poor soul work out how to do it and treat yourself to something nice.
Chris Mohan --- Internet Storm Center Handler on Duty
(c) SANS Internet Storm Center. http://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.