I have a site in my internal network that has a valid certificate for it's external hostname (blabla.example.com). But when I access it from my LAN I use it's IP address to connect to it and Chrome emits a warning due to the fact the hostname is different than the one used in the certificate. How can I disable this warning for this site or, preferentially for my whole LAN?
acces your site via the external name. for this you have to adjust your dns-resolver to provide the internal ip of your blabla.example.com. since you are a great admin you are able to achieve this :)
(to answer that 2nd part seriously you would have to provide more information about your network-topology or you could search http://serverfault.com)