> Thanks for that and the other responses. > > We indeed tracked it to DNS problems - in this case the onsite admin > (who is a Windows only type) had set up a Smoothwall router and we were > using it as our DNS server. It seems to have been responding with bad > data. > > We changed the server to use OpenDNS servers and all's well. > > Thanks again for the help. > > Kevin
Be careful with OpenDNS: They return false positives, e.g.: > www.abcdefghijklmnop12345.com. Server: resolver1.opendns.com Address: 208.67.222.222 Non-authoritative answer: Name: www.abcdefghijklmnop12345.com Address: 208.67.217.132 This is intended to direct queries for non-existent URLs to OpenDNS's servers. I can't guarantee this will interfere with DNS blacklist operation, but it may. The blacklist relies on NXDOMAIN responses to indicate that a server is "safe". As a result, you may end up blacklisting every server on the Internet since OpenDNS will never indicate a lookup failure. Perhaps someone else can confirm this. Damon
