The remote host is missing an update to bind9 announced via advisory DSA 2272-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202272-1

It was discovered that BIND, a DNS server, does not correctly process certain UPDATE requests, resulting in a server crash and a denial of service. This vulnerability affects BIND installations even if they do not actually use dynamic DNS updates. For the oldstable distribution (lenny), this problem has been fixed in version 1:9.6.ESV.R4+dfsg-0+lenny3. For the stable distribution (squeeze), this problem has been fixed in version 1:9.7.3.dfsg-1~squeeze3. The testing distribution (wheezy) and the unstable distribution (sid) will be fixed later. We recommend that you upgrade your bind9 packages.