Is it possible to trace the delegation path for a DNS lookup?
- by Josh Glover
I'm trying to determine why a Nagios host check is failing (hostnames and IPs have been changed to protect the guilty):
: jmglov@laurana; host www.foo.com
;; connection timed out; no servers could be reached
: jmglov@laurana; for ns in `grep -o '\([0-9]\+[.]\)\{3\}[0-9]\+$' /etc/resolv.conf`; do ping -qc 1 $ns; done
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
--- 192.168.1.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 10.911/10.911/10.911/0.000 ms
PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data.
--- 192.168.1.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.241/0.241/0.241/0.000 ms
So I know that my nameservers are reachable, meaning that some nameserver along the delegation path to the authoritative nameserver for my host is not responding. Is there an easy way to determine which nameserver this is (basically a traceroute for DNS)?