On Monday, December 8, 2014 we'll be updating the Globus file transfer service. As part of this update we're adding another IP address to the service that executes file transfer requests. The majority of our users will see no difference, and any active file transfers will continue without interruption. However, if you have endpoints behind a firewall with tight inbound rules explicitly identifying Globus machines, you will need to update these rules to allow the new IP addresses, otherwise file transfer requests to/from endpoints behind that firewall will fail.
This link has specific information on the IP addresses that should be allowed as part of your firewall configuration. If, after making these changes, you experience issues please contact us. Thanks for your continued support!