diff -ru ppp-2.4.4.orig/pppd/plugins/rp-pppoe/discovery.c ppp-2.4.4/pppd/plugins/rp-pppoe/discovery.c
--- ppp-2.4.4.orig/pppd/plugins/rp-pppoe/discovery.c	2005-03-22 15:22:32.000000000 +0500
+++ ppp-2.4.4/pppd/plugins/rp-pppoe/discovery.c	2009-11-03 11:12:28.000000000 +0500
@@ -369,6 +369,11 @@
 		printErr("Ignoring PADO packet from broadcast MAC address");
 		continue;
 	    }
+	    if (conn->req_peer
+		   && memcmp(packet.ethHdr.h_source, conn->req_peer_mac, ETH_ALEN) != 0) {
+	       warn("Ignoring PADO packet from wrong MAC address");
+	       continue;
+	    }
 	    parsePacket(&packet, parsePADOTags, &pc);
 	    if (!pc.seenACName) {
 		printErr("Ignoring PADO packet with no AC-Name tag");
diff -ru ppp-2.4.4.orig/pppd/plugins/rp-pppoe/plugin.c ppp-2.4.4/pppd/plugins/rp-pppoe/plugin.c
--- ppp-2.4.4.orig/pppd/plugins/rp-pppoe/plugin.c	2006-05-30 05:29:16.000000000 +0600
+++ ppp-2.4.4/pppd/plugins/rp-pppoe/plugin.c	2009-11-03 11:12:28.000000000 +0500
@@ -63,6 +63,8 @@
 static char *acName = NULL;
 static char *existingSession = NULL;
 static int printACNames = 0;
+static char *pppoe_reqd_mac = NULL;
+unsigned char pppoe_reqd_mac_addr[6];
 
 static int PPPoEDevnameHook(char *cmd, char **argv, int doit);
 static option_t Options[] = {
@@ -78,6 +80,8 @@
       "Attach to existing session (sessid:macaddr)" },
     { "rp_pppoe_verbose", o_int, &printACNames,
       "Be verbose about discovered access concentrators"},
+    { "pppoe-mac", o_string, &pppoe_reqd_mac,
+      "Only connect to specified MAC address" },
     { NULL }
 };
 
@@ -381,6 +385,21 @@
 
 void pppoe_check_options(void)
 {
+    unsigned int mac[6];
+    int i;
+
+    if (pppoe_reqd_mac != NULL) {
+	if (sscanf(pppoe_reqd_mac, "%x:%x:%x:%x:%x:%x",
+		   &mac[0], &mac[1], &mac[2], &mac[3],
+		   &mac[4], &mac[5]) != 6) {
+	    option_error("cannot parse pppoe-mac option value");
+	    exit(EXIT_OPTION_ERROR);
+	}
+	for (i = 0; i < 6; ++i)
+	    conn->req_peer_mac[i] = mac[i];
+	conn->req_peer = 1;
+    }
+
     lcp_allowoptions[0].neg_accompression = 0;
     lcp_wantoptions[0].neg_accompression = 0;
 
diff -ru ppp-2.4.4.orig/pppd/plugins/rp-pppoe/pppoe.h ppp-2.4.4/pppd/plugins/rp-pppoe/pppoe.h
--- ppp-2.4.4.orig/pppd/plugins/rp-pppoe/pppoe.h	2004-11-04 15:07:37.000000000 +0500
+++ ppp-2.4.4/pppd/plugins/rp-pppoe/pppoe.h	2009-11-03 11:12:28.000000000 +0500
@@ -254,6 +254,8 @@
     int sessionSocket;		/* Raw socket for session frames */
     unsigned char myEth[ETH_ALEN]; /* My MAC address */
     unsigned char peerEth[ETH_ALEN]; /* Peer's MAC address */
+    unsigned char req_peer_mac[ETH_ALEN]; /* required peer MAC address */
+    unsigned char req_peer;	/* require mac addr to match req_peer_mac */
     UINT16_t session;		/* Session ID */
     char *ifName;		/* Interface name */
     char *serviceName;		/* Desired service name, if any */