diff -Nru initramfs-tools-0.125ubuntu3/debian/changelog initramfs-tools-0.125ubuntu4/debian/changelog
--- initramfs-tools-0.125ubuntu3/debian/changelog	2016-08-26 10:54:37.000000000 +0000
+++ initramfs-tools-0.125ubuntu4/debian/changelog	2016-09-21 14:26:01.000000000 +0000
@@ -1,3 +1,12 @@
+initramfs-tools (0.125ubuntu4) yakkety; urgency=medium
+
+  * scripts/functions: by default, when setting up networking, use dhclient if
+    we're asked to do DHCP explicitly, or if we otherwise are expected to do
+    things automatically. This way we can bring up both IPv4 and IPv6, as
+    klibc doesn't support IPv6. (LP: #1621507)
+
+ -- Mathieu Trudel-Lapierre <cyphermox@ubuntu.com>  Wed, 21 Sep 2016 10:26:01 -0400
+
 initramfs-tools (0.125ubuntu3) yakkety; urgency=medium
 
   * init: Revert Debian commit ab91306. Interpreting "rootdelay" as a static
diff -Nru initramfs-tools-0.125ubuntu3/scripts/functions initramfs-tools-0.125ubuntu4/scripts/functions
--- initramfs-tools-0.125ubuntu3/scripts/functions	2016-07-07 15:48:08.000000000 +0000
+++ initramfs-tools-0.125ubuntu4/scripts/functions	2016-09-21 14:26:01.000000000 +0000
@@ -276,11 +276,18 @@
 		none|off)
 			# Do nothing
 			;;
-		""|on|any)
+		""|::::*|on|any|dhcp)
+			# if IP contains something other than BOOTIF; use that
+			# interface to bring up the network.
+			if ! echo "${IP}" | grep -qc 'BOOTIF'; then
+				DEVICE="${IP#*:*:*:*:*:*}";
+			fi
+
 			# Bring up device
-			ipconfig -t ${ROUNDTTT} "${DEVICE}"
+			dhclient -4 -1 -v "${DEVICE}"
+			dhclient -6 -1 -v "${DEVICE}"
 			;;
-		dhcp|bootp|rarp|both)
+		bootp|rarp|both)
 			ipconfig -t ${ROUNDTTT} -c ${IP} -d "${DEVICE}"
 			;;
 		*)