DNS Attacks question

Ok i heard so much about this DNS attack but i really don't know if i should be concern about it.
i have a Windows 2000 server that has DNS installed on it and i don't see any error messages in the event viewer (not sure if i would). Unfortunately, this server is not up to date with all the MS patches, for some reason it will not connect to the ms update server (i have a ticket it with ms update tech support to help me out on this issue).

i have a Cisco Pix501 that connects us to our parent company. no one there knows anything about this issue with dns attacks and i was hoping someone can help me out here. the Cisco Pix501 was install by a contracting company that our parent company contracted out to do the installation however they did not leave any information for. so i do not know if the Cisco pix501 has anything to do with our DNS.

Any assistance would be greatly appreciated!
Thanks in advance!