Subject Software hangs using VPN
FB 1.56

I have a customer who says our application hands when using a VPN. Any ideas on what to look at with the connection layer? Anything I can set to improve this? I do anticipate moving to FB 3 this year, but I am currently working on a project and it will be a major undertaking to move +1,000 users from 1.56 to 3.

Thank you,

Ed Dressel