diff --git a/repos/os/src/server/nic_router/config.xsd b/repos/os/src/server/nic_router/config.xsd
index 89025f923..9658df8e7 100644
--- a/repos/os/src/server/nic_router/config.xsd
+++ b/repos/os/src/server/nic_router/config.xsd
@@ -167,6 +167,7 @@
 			<xs:attribute name="dhcp_offer_timeout_sec"    type="Seconds" />
 			<xs:attribute name="udp_idle_timeout_sec"      type="Seconds" />
 			<xs:attribute name="tcp_idle_timeout_sec"      type="Seconds" />
+			<xs:attribute name="icmp_idle_timeout_sec"     type="Seconds" />
 			<xs:attribute name="tcp_max_segm_lifetime_sec" type="Seconds" />
 		</xs:complexType>
 	</xs:element><!-- config -->