diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index cd0c6c637b91..e56401008b5f 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -189,6 +189,16 @@ This action does not automatically disable routes using the interface.
 .\" IP encapsulation of
 .\" .Tn CLNP
 .\" packets is done differently.
+.It Cm lladdr Ar addr
+Set the link-level address on an interface. This can be used to
+e.g. set a new MAC address on an ethernet interface, though the
+mechanism used is not ethernet-specific. The address
+.Ar addr
+is specified as a series of colon-separated hex digits.
+If the interface is already
+up when this option is used, it will be briefly brought down and
+then brought back up again in order to insure that the receive
+filter in the underlying ethernet hardware is properly reprogrammed.
 .It Cm media Ar type
 If the driver supports the media selection system, set the media type
 of the interface to
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index a3c75ca8f89b..52d403d1a680 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -53,6 +53,7 @@ static const char rcsid[] =
 #include <sys/module.h>
 #include <sys/linker.h>
 
+#include <net/ethernet.h>
 #include <net/if.h>
 #include <net/if_var.h>
 #include <net/if_dl.h>
@@ -153,7 +154,7 @@ c_func	setifprefixlen;
 c_func	setip6flags;
 #endif
 c_func	setifipdst;
-c_func	setifflags, setifmetric, setifmtu;
+c_func	setifflags, setifmetric, setifmtu, setiflladdr;
 
 
 #define	NEXTARG		0xffffff
@@ -212,6 +213,7 @@ struct	cmd {
 	{ "compress",	IFF_LINK0,	setifflags },
 	{ "noicmp",	IFF_LINK1,	setifflags },
 	{ "mtu",	NEXTARG,	setifmtu },
+	{ "lladdr",	NEXTARG,	setiflladdr },
 	{ 0,		0,		setifaddr },
 	{ 0,		0,		setifdstaddr },
 };
@@ -815,6 +817,29 @@ setifmtu(val, dummy, s, afp)
 		warn("ioctl (set mtu)");
 }
 
+void
+setiflladdr(val, dummy, s, afp)
+	const char *val;
+	int dummy __unused;
+	int s;
+	const struct afswtch *afp;
+{
+	struct ether_addr	*ea;
+
+	ea = ether_aton(val);
+	if (ea == NULL) {
+		warn("malformed link-level address");
+		return;
+	}
+	strncpy(ifr.ifr_name, name, sizeof (ifr.ifr_name));
+	ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
+	ifr.ifr_addr.sa_family = AF_LINK;
+	bcopy(ea, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
+	if (ioctl(s, SIOCSIFLLADDR, (caddr_t)&ifr) < 0)
+		warn("ioctl (set lladdr)");
+
+	return;
+}
 
 #define	IFFBITS \
 "\020\1UP\2BROADCAST\3DEBUG\4LOOPBACK\5POINTOPOINT\6SMART\7RUNNING" \
diff --git a/sys/net/if.c b/sys/net/if.c
index c328575bfd26..2dce111ec22c 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -52,6 +52,7 @@
 #include <sys/sysctl.h>
 
 #include <net/if.h>
+#include <net/if_arp.h>
 #include <net/if_dl.h>
 #include <net/radix.h>
 #include <net/route.h>
@@ -763,6 +764,8 @@ ifioctl(so, cmd, data, p)
 {
 	register struct ifnet *ifp;
 	register struct ifreq *ifr;
+	register struct ifaddr *ifa;
+	struct sockaddr_dl *sdl;
 	struct ifstat *ifs;
 	int error;
 	short oif_flags;
@@ -912,6 +915,33 @@ ifioctl(so, cmd, data, p)
 			return (EOPNOTSUPP);
 		return ((*ifp->if_ioctl)(ifp, cmd, data));
 
+	case SIOCSIFLLADDR:
+		error = suser(p);
+		if (error)
+			return (error);
+		ifa = ifnet_addrs[ifp->if_index - 1];
+		if (ifa == NULL)
+			return(EINVAL);
+		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+		if (sdl == NULL)
+			return(EINVAL);
+		bcopy(ifr->ifr_addr.sa_data,
+		    ((struct arpcom *)ifp->if_softc)->ac_enaddr,
+		    ifr->ifr_addr.sa_len);
+		bcopy(ifr->ifr_addr.sa_data, LLADDR(sdl),
+		    ifr->ifr_addr.sa_len);
+		/*
+		 * If the interface is already up, we need
+		 * to re-init it in order to reprogram its
+		 * address filter.
+		 */
+		if (ifp->if_flags & IFF_UP) {
+			ifp->if_flags &= ~IFF_UP;
+			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, NULL);
+			ifp->if_flags |= IFF_UP;
+			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, NULL);
+		}
+		return(0);
 	default:
 		oif_flags = ifp->if_flags;
 		if (so->so_proto == 0)
diff --git a/sys/sys/sockio.h b/sys/sys/sockio.h
index 1e649a18074f..efa3cbc89730 100644
--- a/sys/sys/sockio.h
+++ b/sys/sys/sockio.h
@@ -94,5 +94,6 @@
 #define	SIOCGIFGENERIC	_IOWR('i', 58, struct ifreq)	/* generic IF get op */
 
 #define	SIOCGIFSTATUS	_IOWR('i', 59, struct ifstat)	/* get IF status */
+#define	SIOCSIFLLADDR	_IOW('i', 60, struct ifreq)	/* set link level addr */
 
 #endif /* !_SYS_SOCKIO_H_ */