diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -2618,6 +2618,7 @@
 	case DHO_BOOTFILE_NAME:
 	case DHO_DHCP_USER_CLASS_ID:
 	case DHO_URL:
+	case DHO_SIP_SERVERS:
 	case DHO_END:
 		return (1);
 	case DHO_CLASSLESS_ROUTES:
diff --git a/sbin/dhclient/dhcp.h b/sbin/dhclient/dhcp.h
--- a/sbin/dhclient/dhcp.h
+++ b/sbin/dhclient/dhcp.h
@@ -172,6 +172,7 @@
 #define DHO_DHCP_USER_CLASS_ID		77
 #define	DHO_URL				114
 #define	DHO_DOMAIN_SEARCH		119
+#define DHO_SIP_SERVERS			120
 #define DHO_CLASSLESS_ROUTES		121
 #define DHO_END				255