why this query cause ServFail

We've been seeing sporadic failure of resolve this name web1.production.tacc.utexas.edu from our nameserver. There are 6 NS listed for domain production.tacc.utexas.edu, two of the six don't seem to work(dc1.production.tacc.utexas.edu 129.114.13.17 and dc2.production.tacc.utexas.edu 129.114.13.18)

Re: why this query cause ServFail

Also should mention that our BIND is 9.9.8-P4, what confuses me here is that the listed nameserver (129.114.13.18) is lame and our nameserver ( 192.168.1.100) can't get any responses from it(see tcpdump above), why our nameserver try other listed NS servers instead sending 'ServFail' to the client

Re: why this query cause ServFail

Hi Hillary, By default, BIND will return SERVFAIL to the client if it can't complete the full iteration process within 10 seconds. This is controllable by the "resolver-query-timeout" parameter. As for why your recursive server doesn't just try elsewhere, it _will_, but it assumes that it's quer