https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=782450
https://bugs.gentoo.org/546554

--- ppp-2.4.7/pppd/plugins/radius/util.c
+++ ppp-2.4.7/pppd/plugins/radius/util.c
@@ -77,7 +77,7 @@
   static unsigned short int cnt = 0;
   sprintf (buf, "%08lX%04X%02hX",
 	   (unsigned long int) time (NULL),
-	   (unsigned int) getpid (),
+	   (unsigned int) getpid () % 65535,
 	   cnt & 0xFF);
   cnt++;
   return buf;