Reference client fails when PTR returns SERVFAIL

[nkinkade]

$ host ndt.iupui.mlab1.mia02.measurement-lab.org
ndt.iupui.mlab1.mia02.measurement-lab.org has address 38.109.21.11
$ host 38.109.21.11
Host 11.21.109.38.in-addr.arpa not found: 2(SERVFAIL)
$ web100clt -n ndt.iupui.mlab1.mia02.measurement-lab.org --disablemid --disablesfw
Testing network path for configuration and performance problems  --  Using IPv4 address
running 10.0s outbound test (client to server) . . . . .  0.00 kb/s
[2018-02-12T10:29:36.735087Z pid=16761 loglevel=0          network.c:363 ] Failed to connect: Connection refused
[2018-02-12T10:29:36.735316Z pid=16761 loglevel=0          network.c:368 ] No sockets could be created that match requirements.
[2018-02-12T10:29:36.735367Z pid=16761 loglevel=0     test_s2c_clt.c:170 ] Connect() for Server to Client failed (connection 477210661)
[2018-02-12T10:29:36.735519Z pid=16761 loglevel=0        web100clt.c:956 ] S2C throughput test FAILED!
[2018-02-12T10:29:36.735626Z pid=16761 loglevel=0    test_meta_clt.c:62  ] Protocol error - missed prepare message!
[2018-02-12T10:29:36.735688Z pid=16761 loglevel=0        web100clt.c:979 ] META test FAILED!
[2018-02-12T10:29:36.735782Z pid=16761 loglevel=0        web100clt.c:1006] Protocol error - expected results!  got '', msgtype=2

The client appears to attempt 4 PTR lookups before starting the NDT test.