Comment 16 for bug 175316

iputils-ping in bionic and artful is linked with libidn:

andreas@nsnx:~$ dpkg -S /bin/ping
iputils-ping: /bin/ping

andreas@nsnx:~$ ldd /bin/ping|grep idn
 libidn.so.11 => /lib/x86_64-linux-gnu/libidn.so.11 (0x00007f21be770000)

andreas@nsnx:~$ ping -c 1 räksmörgås.se
PING räksmörgås.se (91.226.36.2) 56(84) bytes of data.
64 bytes from common33.iis.se (91.226.36.2): icmp_seq=1 ttl=46 time=250 ms

--- räksmörgås.se ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 250.386/250.386/250.386/0.000 ms

Confirming that's not the case in xenial.

ubuntu@xenial-ping:~$ ping bjørvika.uio.nornet
ping: unknown host bjørvika.uio.nornet
ubuntu@xenial-ping:~$ ldd /bin/ping
 linux-vdso.so.1 => (0x00007ffddd516000)
 libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007f68883fe000)
 libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f6888034000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f6888604000)

I'm gonna mark the iputils task as fix released then.