diff -Naur ppp-2.4.4/pppd/auth.c ppp-2.4.4-ipparam/pppd/auth.c
--- ppp-2.4.4/pppd/auth.c	2007-12-08 16:29:16 +0200
+++ ppp-2.4.4-ipparam/pppd/auth.c	2007-12-08 21:09:23 +0200
@@ -2564,7 +2564,8 @@
     argv[3] = user_name;
     argv[4] = devnam;
     argv[5] = strspeed;
-    argv[6] = NULL;
+    argv[6] = ipparam;
+    argv[7] = NULL;
 
     auth_script_pid = run_program(script, argv, 0, auth_script_done, NULL, 0);
 }