Solution #00004302
Scope:
All Barracuda Web Filters, firmware 4.0 or higher
Answer:
If your DNS server includes a wildcard DNS record, or somewhere in its authority chain a wildcard entry exists, this can cause your Spyware Removal Tool to not function properly. A wildcard DNS record is a record in a DNS zone that will match requests for non-existent domain names. A wildcard DNS record is specified by using a "*" as the left most label (part) of a domain name (e.g. *.example.com).
Test your DNS service, execute either a dig or nslookup for a non-existent domain.
Example:
Y:\> nslookup sheatemyhomework.com
Server: 208.67.222.222
Address: 10.4.1.90
Non-authoritative answer:
Name: sheatemyhomework.com
Address: 208.67.216.132
Y:\> nslookup qwerlkljhtd.com
Server: 208.67.222.222
Address: 10.4.1.90
Non-authoritative answer:
Name: qwerlkljhtd.com
Address: 208.67.216.132
NOTE: For both domains, the server has returned the same address, despite the fact that neither domain actually exists.
The correct response should look like this:
Y:\> nslookup sheatemyhomework.com
Server: dns01.mydomain.local
Address: 10.4.1.90
*** dns01.mydomain.local can't find sheatemyhomework.com: Non-existent domain
If your server is returning the incorrect response for non-existent domains, you can do one of two things to get your spyware removal tool working.
- Create and IP Block for the false IP address provided by the DNS service
- Redirect your DNS queries to a service that does not contain wildcard records.
If you still have difficulty getting the spyware removal tool to run properly, contact Barracuda Networks Technical Support for further assistance.
Link to this page:
https://campus.barracuda.com/solution/50160000000Hpm1AAC