diff --git a/package/network/services/ppp/files/lib/netifd/ppp-up b/package/network/services/ppp/files/lib/netifd/ppp-up
index 105ecbe844..7511042639 100755
--- a/package/network/services/ppp/files/lib/netifd/ppp-up
+++ b/package/network/services/ppp/files/lib/netifd/ppp-up
@@ -25,6 +25,7 @@ if [ -n "$AUTOIPV6" ]; then
 	json_add_string name "${PPP_IPPARAM}_6"
 	json_add_string ifname "@$PPP_IPPARAM"
 	json_add_string proto "dhcpv6"
+	[ -n "$EXTENDPREFIX" ] && json_add_string extendprefix 1
 	json_close_object
 	ubus call network add_dynamic "$(json_dump)"
 fi
diff --git a/package/network/utils/comgt/files/3g.sh b/package/network/utils/comgt/files/3g.sh
index 968662675b..8aecb0fd62 100644
--- a/package/network/utils/comgt/files/3g.sh
+++ b/package/network/utils/comgt/files/3g.sh
@@ -89,6 +89,9 @@ proto_3g_setup() {
 		;;
 	esac
 
+	# Enable RFC 7278
+	proto_export "EXTENDPREFIX=1"
+
 	connect="${apn:+USE_APN=$apn }DIALNUMBER=$dialnumber /usr/sbin/chat -t5 -v -E -f $chat"
 	ppp_generic_setup "$interface" \
 		noaccomp \
diff --git a/package/network/utils/comgt/files/directip.sh b/package/network/utils/comgt/files/directip.sh
index 66d92a7c2c..d82805278c 100644
--- a/package/network/utils/comgt/files/directip.sh
+++ b/package/network/utils/comgt/files/directip.sh
@@ -86,6 +86,7 @@ proto_directip_setup() {
 	json_add_string name "${interface}_6"
 	json_add_string ifname "@$interface"
 	json_add_string proto "dhcpv6"
+	json_add_string extendprefix 1
 	ubus call network add_dynamic "$(json_dump)"
 
 	return 0
diff --git a/package/network/utils/comgt/files/ncm.sh b/package/network/utils/comgt/files/ncm.sh
index 1f0d0db2e7..ffe5615e07 100644
--- a/package/network/utils/comgt/files/ncm.sh
+++ b/package/network/utils/comgt/files/ncm.sh
@@ -131,6 +131,7 @@ proto_ncm_setup() {
 	json_add_string name "${interface}_6"
 	json_add_string ifname "@$interface"
 	json_add_string proto "dhcpv6"
+	json_add_string extendprefix 1
 	ubus call network add_dynamic "$(json_dump)"
 }
 
diff --git a/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh b/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
index db0c7b0c3c..f8b2c06b67 100755
--- a/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
+++ b/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
@@ -137,6 +137,7 @@ _proto_mbim_setup() {
 	json_add_string name "${interface}_6"
 	json_add_string ifname "@$interface"
 	json_add_string proto "dhcpv6"
+	json_add_string extendprefix 1
 	ubus call network add_dynamic "$(json_dump)"
 }
 
diff --git a/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh b/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
index 25e5d1f521..b416da6bc8 100755
--- a/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
+++ b/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
@@ -128,6 +128,7 @@ _proto_qmi_setup() {
 	json_add_string name "${interface}_6"
 	json_add_string ifname "@$interface"
 	json_add_string proto "dhcpv6"
+	json_add_string extendprefix 1
 	json_close_object
 	ubus call network add_dynamic "$(json_dump)"
 }