Comment 17 for bug 1604010

Am affected by the missing sntp binary also.

For reference the Debian bug mentioned in comment #4 is https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=793837.

Also note that the workaround mentioned in #15 does not (AFAICT from https://github.com/ntp-project/ntp/blob/master/ntpdate/ntpdate.c) use the SNTP protocol, so it does not serve identical function as the sntp tool.

Installing package rdate will give you the rdate tool which can retrieve time using the SNTP protocol using its -n option (-p here for just printing the retrieved date):
$ rdate -n -p ntp.ubuntu.com
Wed May 24 13:14:52 UTC 2017

Also note that on Ubuntu 16.04 by default time synchronization has been taken over by systemd's timesyncd (man systemd-timesyncd), so neither package ntp (with execs ntpd and missing sntp) or package ntpdate are necessary for a machine to synchronize its time against a NTP server. Read something about that in https://help.ubuntu.com/lts/serverguide/NTP.html which is a fine intermingled mess of ntpd and timesyncd instructions.