Index: ifconfig.8
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.8,v
retrieving revision 1.399
diff -u -p -r1.399 ifconfig.8
--- ifconfig.8	11 Jan 2024 17:22:04 -0000	1.399
+++ ifconfig.8	31 Mar 2024 23:40:35 -0000
@@ -1985,6 +1985,29 @@ multipoint-to-multipoint modes).
 .It Cm -vnetid
 Clear the virtual network identifier.
 .El
+.Sh OVERLAY
+.nr nS 1
+.Bk -words
+.Nm ifconfig
+.Ar interface
+.Op Cm endpoint Ar ip-address Ar ether-address
+.Ek
+.nr nS 0
+.Pp
+.Xr nvgre 4
+and
+.Xr vxlan 4
+interfaces overlay Ethernet networks on top of IP underlay networks.
+The following options are available:
+.Bl -tag -width Ds
+.It Cm endpoint Ar ip-address Ar ether-address
+Add a static entry for
+.Ar ether-address
+into the address cache pointing to
+.Ar ip-address .
+Static entries are never aged out of the cache or replaced, even if the address
+is seen on a different interface.
+.El
 .Sh UMB
 .nr nS 1
 .Bk -words