I m having one 2811 Cisco router for internet connection. There is a firewall between router & Lan. Firewall & Router are connected via public IP. NAT is done on Firewall which is hiding my whole lan behind one public ip(i.e. ip on firewall interface which is directly connecting internet router.) I have permitted my PC from firewall to access the inernet router. So i am able to telnet that router. But i can't ping my PC (as it is private ip). So how can i take the backup of that router.