The authenticity of host 'github.com (192.30.252.128)' can't be established

Question

I am trying to use

sudo npm install

to install all my dependencies for an application written in nodejs. My OS is Ubuntu 13.04

How

Answer 1

Run ssh github.com and type yes and it should fail. Then run your command again. If not try ssh github.com again as they have multiple IP's and you might need all of them.