Linking two Asterisk Servers together

I am trying to link two asterisk servers together to be able to make calls from Asterisk B to Asterisk A. I add the IP address of Asterisk B to Asterisk A to allow communication but the moment I do this I can no longer make any outgoing or recieve incoming phone calls on box A. Is this a problem that anyone has encountered before?

How are you adding the IP address of one to the other? Are you using plain Asterisk, or are you using some interface on top of Asterisk?

Follow the following link to intreconnect two asterisk bix using either iax or through sip trunks