Internal outlook users cannot connect to Exchange Server 2013

Hi Everyone,

I installed exchange 2013, already added an SRV for autodiscover on my external DNS, my problem is when I'm on a public network or on my house networt, which doesnt have any firewall (directly connected to the internet). I can connect my outlook to the Exchange server. When I'm @ the office (Internal Network) I'm having issues, we cannot connect to the Exchange Server. Is there any ports? or application control? that we need to allow on the internal security?

Thanks,

MIkey Cunanan

MSI-ECS