Racker Hacker

I was recently working on a server where a user on the server was concerned with these log messages:

Oct 7 20:59:33 web named[13698]: client 111.222.333.444#50389: updating zone ‘domain.com/IN’: update failed: ‘RRset exists (value dependent)’ prerequisite not satisfied (NXRRSET)
Oct 7 20:59:34 web named[13698]: client 111.222.333.444#50392: update ‘domain.com/IN’ denied
Oct 7 21:59:35 web named[13698]: client 111.222.333.444#50422: updating zone ‘domain.com/IN’: update failed: ‘RRset exists (value dependent)’ prerequisite not satisfied (NXRRSET)
Oct 7 21:59:35 web named[13698]: client 111.222.333.444#50425: update ‘domain.com/IN’ denied
Oct 7 22:59:20 web named[13698]: client 111.222.333.444#50458: updating zone ‘domain.com/IN’: update failed: ‘RRset exists (value dependent)’ prerequisite not satisfied (NXRRSET)

The messages here are actually showing that named is doing its job well. Some user was attempting to dynamically update a DNS zone repeatedly, but named was rejecting the updates since they were not coming from a valid sources.

Further reading:
Zytrax.com: DNS BIND Zone Transfers and Updates
Internet Systems Consortium: Dynamic Updates

This entry was posted on Wednesday, October 10th, 2007 at 12:13 pm and is filed under Security.You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.