Red Hat Bugzilla – Bug 13906
nslookup -q=A != nslookup set type=A (in utility mode)
Last modified: 2008-05-01 11:37:56 EDT
I discovered this while trying to query a DNS server. Here, let me demonstrate. -- demonstration-- samkaski@vortex:~$ nslookup -q=A irc.fi.quakenet.eu.org ns1.quakenet.eu.org *** Can't find server name for address 194.192.186.225: Server failed *** Default servers are not available samkaski@vortex:~$ 18:17:57.586699 eth1 > 212.90.74.152.1030 > 194.192.186.225.domain: 3653+ PTR? 225.186.192.194.in-addr.arpa. (46) (DF) (ttl 64, id 0) 18:17:57.672753 eth1 < 194.192.186.225.domain > 212.90.74.152.1030: 3653 ServFail 0/0/0 (46) (ttl 53, id 47931) samkaski@vortex:~$ nslookup Default Server: localhost Address: 127.0.0.1 > server ns1.quakenet.eu.org Default Server: ns1.quakenet.eu.org Address: 194.192.186.225 > set type=A > irc.fi.quakenet.eu.org Server: ns1.quakenet.eu.org Address: 194.192.186.225 Name: irc.fi.quakenet.eu.org Address: 128.214.123.8 > exit 18:18:48.433937 eth1 > 212.90.74.152.1030 > 194.192.186.225.domain: 13517+ A? irc.fi.quakenet.eu.org. (40) (DF) (ttl 64, id 0) 18:18:48.492745 eth1 < 194.192.186.225.domain > 212.90.74.152.1030: 13517* 1/2/2 irc.fi.quakenet.eu.org. A 128.214.123.8 (139) (ttl 53, id 47947) --demonstration-- What this means is that when nslookup is used from the command line to search for a A type record it incorrectly tries to resolve the PTR record for the given DNS server. This might or might not be an issue (depends if the remote server allows PTR-queries or not). Dig works correctly. samkaski@vortex:~$ rpm -qa|grep ^bind-utils bind-utils-8.2.2_P5-9 samkaski@vortex:~$
This is how nslookup works. Just try e.g. 'nslookup -q=A irc.fi.quakenet.eu.org ns.funet.fi'. You'll get answer nice and neat. The thing here is that nslookup (used in this way) first asks the specified server a PTR of its own address (here 225.186.192.194.in-addr.arpa.). That server/zone in question can't handle the situation; It has been misconfigured.