Comodo Directory

I am trying to use the Comodo.Directory.com location for SecureZip email certificates.
At my company we lock down the Firewall pretty good. In the secureZip configuration I see Comodo.Directory.com, port 389 is the location or path th the public directory. However in our Firewall we need to put an IP address.
A Ping shows me that Comodo.Directory.com is 91.199.212.168
My question is if we open port 389 at this IP address, will this suffice and allow SecureZip to find the publshed Certificates there, or will the IP ever change? (static ?)

Thanks Joe

Hi,

Can you please submit the ticket in the following link
http://support.comodo.com/index.php?_m=tickets&_a=submit