I'm trying to create a Site to Site VPN tunnel between a Cisco Concentrator and a Juniper Concentrator. The tunnel forms and there are no error messages in the log files but data will only transmit one way. Ping packets can successfully travel from the Cisco end to the Juniper end, but replies fail to get past the Juniper back to the Cisco Concentrator.
Has anyone any suggestions? I have ruled out Firewalls etc.