View source for KB 153

===How do I set up a Cisco 678 router to forward GRE for PPTP connections?===
 Article:153
 Created:2002-04-05 11:41:37
 Categories:
   Windows 95
   Windows 98
   Windows NT 4
   Windows 2000
   DSL
   Windows XP

====Question or Symptom====
How do I set up a Cisco 678 router to forward GRE for PPTP connections?


====Resolution====
From enable mode type:
  
set nat ent add <internal_machine_ip> 0 47
set nat ent add <internal_machine_ip> 1723 tcp
  

internal_machine_ip represents your server's local IP address. 0 allows all ports
and 47 is for GRE protocol.  PPTP is the only VPN protocol that is known to us to
work through NAT this way.