diff -Naur ppp-2.4.4-upto52/pppd/options.c ppp-2.4.4/pppd/options.c

--- ppp-2.4.4-upto52/pppd/options.c	2007-12-08 21:52:54 +0300

+++ ppp-2.4.4/pppd/options.c	2007-12-08 21:56:20 +0300

@@ -119,6 +119,7 @@

 bool	tune_kernel;		/* may alter kernel settings */

 int	connect_delay = 1000;	/* wait this many ms after connect script */

 int	req_unit = -1;		/* requested interface unit */

+int	req_minunit = -1;	/* requested minimal interface unit */

 char	req_ifname[MAXIFNAMELEN];	/* requested interface name */

 bool	multilink = 0;		/* Enable multilink operation */

 char	*bundle_name = NULL;	/* bundle name for multilink */

@@ -287,6 +288,9 @@

     { "unit", o_int, &req_unit,

       "PPP interface unit number to use if possible",

       OPT_PRIO | OPT_LLIMIT, 0, 0 },

+    { "minunit", o_int, &req_minunit,

+      "PPP interface minimal unit number",

+      OPT_PRIO | OPT_LLIMIT, 0, 0 },

     { "ifname", o_string, req_ifname,

       "Set PPP interface name",

diff -Naur ppp-2.4.4-upto52/pppd/pppd.8 ppp-2.4.4/pppd/pppd.8

--- ppp-2.4.4-upto52/pppd/pppd.8	2007-12-08 21:52:54 +0300

+++ ppp-2.4.4/pppd/pppd.8	2007-12-08 21:53:34 +0300

@@ -1051,6 +1051,12 @@

 Set the ppp interface name for outbound connections.  A failure to set the

 name will terminate the pppd.

 .TP

+.B minunit \fInum

+Such as unit, but always select bigger interface

+.TP

+.B minunit \fInum

+PPP interface minimal unit number. Such as unit, but always select bigger interface

+.TP

 .B updetach

 With this option, pppd will detach from its controlling terminal once

 it has successfully established the ppp connection (to the point where

diff -Naur ppp-2.4.4-upto52/pppd/pppd.h ppp-2.4.4/pppd/pppd.h

--- ppp-2.4.4-upto52/pppd/pppd.h	2007-12-08 21:52:54 +0300

+++ ppp-2.4.4/pppd/pppd.h	2007-12-08 21:55:46 +0300

@@ -87,6 +87,7 @@

 #define MAXARGS		1	/* max # args to a command */

 #define MAXNAMELEN	256	/* max length of hostname or name for auth */

 #define MAXSECRETLEN	256	/* max length of password or secret */

+#define MAXUNIT		255	/* max ppp interface */

 #define MAXIFNAMELEN	32	/* max length of interface name; or use IFNAMSIZ, can we

 				   always include net/if.h? */

@@ -329,6 +330,7 @@

 extern int	connect_delay;	/* Time to delay after connect script */

 extern int	max_data_rate;	/* max bytes/sec through charshunt */

 extern int	req_unit;	/* interface unit number to use */

+extern int	req_minunit;	/* interface minimal unit number to use */

 extern char	req_ifname[MAXIFNAMELEN];	/* interface name to use */

 extern bool	multilink;	/* enable multilink operation */

 extern bool	noendpoint;	/* don't send or accept endpt. discrim. */

diff -Naur ppp-2.4.4-upto52/pppd/sys-linux.c ppp-2.4.4/pppd/sys-linux.c

--- ppp-2.4.4-upto52/pppd/sys-linux.c	2007-12-08 21:52:54 +0300

+++ ppp-2.4.4/pppd/sys-linux.c	2007-12-08 21:53:34 +0300

@@ -630,13 +630,26 @@

 	    || fcntl(ppp_dev_fd, F_SETFL, flags | O_NONBLOCK) == -1)

 		warn("Couldn't set /dev/ppp to nonblock: %m");

-	ifunit = req_unit;

-	x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);

-	if (x < 0 && req_unit >= 0 && errno == EEXIST) {

+	if (req_minunit > -1) {

+	    for(ifunit = req_minunit;req_minunit < MAXUNIT; ifunit = ++req_minunit) {

+		x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);

+		if (x < 0 && errno == EEXIST) {

+		    warn("Couldn't allocate PPP unit %d as it is already in use try to attempt next", req_minunit);

+		}

+		if (x >= 0)

+		    break;

+	    }

+	}

+	if ((x < 0) || (req_minunit == -1)) {

+	    ifunit = req_unit;

+	    x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);

+	    if (x < 0 && req_unit >= 0 && errno == EEXIST) {

 		warn("Couldn't allocate PPP unit %d as it is already in use", req_unit);

 		ifunit = -1;

 		x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);

+	    }

 	}

+

 	if (x < 0)

 		error("Couldn't create new ppp unit: %m");