In light of the latest round of attacks against and/or hijacking of DNS, it occurred to me that most people really don’t know what to do about it. More importantly, many companies don’t even notice they’ve been attacked until a customer complains. Especially for smaller companies who may not have as many customers, or only accept comments through a website, they may never know unless they randomly check, or the attacker releases the site and the flood of complaints comes rolling in after the fact.
So I wrote a little tool called “dnstest.pl” (yes a Perl script) that can be run out of cron and can monitor one or more hostname-to-IP-address pairs of sites that are critical to you. If anything happens it’ll send you an alert via email. There are other tools that do this or similar things, but it’s another tool in your arsenal; and most importantly dnstest is meant to be very lightweight and simple to use. You can download dnstest here.
Of course this is only the first step. Reacting quickly to the alert simply reduces the outage and the chance of customer complaints or similar damage. If you like it but want it to do something else, go ahead and fork it. Enjoy!