My name is Paul and I work as a Junior Network Engineer for a small company based in South London. I have been tasked with adding a NATed subnet to our internal LAN (for testing purposes) which I have managed to achieve but I have run into a roadblock when trying to establish communications to the internet. From the NATed subnet, I can ping out to our office LAN and the ping reaches our Firewall (default gateway), but I am unable to go past that. For instance I am unable to ping to the google dns server (18.104.22.168) and from the server based on the NATed LAN, I cannot reach the web via Internet Explorer. I can ping all units in our office LAN from the NATed subnet with no issues. Would it be neccessary to configure port forwarding for http and ICMP to communicate with anything on the internet? Apolgies if this question sounds very simplistic - I am a bit of a networking noob so any advice would be greatly appreciated. Ps The router I have added internally is a Cisco 877. I can also post the configuration applied to the 877 if necessary.
Thanks very much for your help in advance.