On 1/09/2015 6:56 PM, Mark Darvill wrote:
  No I replaced the Hub 5 with a Cisco 1941 with an 1841
and
 Decbrouter90 behind it due to the relatively complex setup I have
 here. The Decbrouter90 handles the GRE tunnels as there is a bug with
 having GRE on a Cisco router that also has NAT enabled. 
What bug are you experiencing?  I have a Cisco 1841 that has NAT 
enabled, hooks into the HECnet as well as connecting a number of 
GRE/IPsec tunnels an IPv6 tunnel and more.  I've not had any 
trouble...that I've noticed.
Regards, Tim.