can't ping my N4

[tpd15]

Hi,

I'm having trouble getting an IP webcam program to work, as I can't seem to connect to my phone through the routers both at home and at work. I've tried to ping the phone's IP address and in return I get this message, "Request timed out". I haven't updated the routers firmware recently. Any ideas what could be causing this?

Thanks,
Toby.