05 August, 2014

ping reverse dns

Slightly unexpected hostname lookup on a CNAME.

maven.op is a CNAME to lulu; the reverse DNS points only to lulu.

Someone has already figured out the lulu hostname by the first line of output because it's shown there. But the ping lines for a few seconds show the name I gave and then turn to the "real" hostname (perhaps when a reverse DNS happens? rather than using the name that we looked up forward-wise to begin with?)

No big deal, but slightly unexpected.

benc@utsire:~$ ping maven.ops.xeus.co.uk
PING lulu.xeus.co.uk (46.4.100.47) 56(84) bytes of data.
64 bytes from maven.ops.xeus.co.uk (46.4.100.47): icmp_req=1 ttl=51 time=466 ms
64 bytes from maven.ops.xeus.co.uk (46.4.100.47): icmp_req=2 ttl=51 time=51.1 ms
64 bytes from maven.ops.xeus.co.uk (46.4.100.47): icmp_req=3 ttl=51 time=51.9 ms
64 bytes from lulu.xeus.co.uk (46.4.100.47): icmp_req=4 ttl=51 time=60.1 ms
64 bytes from lulu.xeus.co.uk (46.4.100.47): icmp_req=5 ttl=51 time=96.5 ms
64 bytes from lulu.xeus.co.uk (46.4.100.47): icmp_req=6 ttl=51 time=50.9 ms
64 bytes from lulu.xeus.co.uk (46.4.100.47): icmp_req=7 ttl=51 time=49.5 ms
64 bytes from lulu.xeus.co.uk (46.4.100.47): icmp_req=8 ttl=51 time=50.6 ms

benc@utsire:~$ ping -V
ping utility, iputils-sss20101006

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