I'm trying to establish one half of a GRE tunnel, the other being configured by my service provider. I have a Cisco PIX-506-E running Firewall version 6.3(5).
Provider Router Public IP: 8.8.8.8 My PIX Public IP: 7.7.7.7
Provider Tunnel Address: 192.168.99.1/30 My Tunnel Address: 192.168.99.2/30