I have a remote site, there i need to connect my Snom D725 with VPN of Head Office firewall. I am using Cyberoam firewall at Head Office.
Please help me to configure the same..
For VPN you need a special firmware, have a look here: http://wiki.snom.com/VPN_Support
For configuration, see this link: http://wiki.snom.com/Networking/Virtual_Private_Network_(VPN) .
Also make sure you have an NTP server to make sure the phones have a valid date.