Q:

Securely publish Outlook Web Access on Exchange 2007 without ISA server

Is there a way to securely publish Outlook Web Access on Exchange 2007 without the need of an ISA server?

A:

It depends on your definition of secure. Many companies expose their client access servers to the internet with nothing but a traditional firewall in front of it, opening just port 443. If you do this, you'd be wise to monitor the Microsoft monthly patches and keep the server up to date with Windows and Exchange patches. If you're not comfortable doing this, then by definition you're looking for an application firewall. ISA is a common choice. Other options are Barracuda's Web Application Firewall or Citrix's NetScaler. If you're using a hardware load balancer, it too might have some application firewall capabilities. For instance, F5 publishes a Deployment Guide for Exchange that includes steps for making Outlook Web Access and other protocols for accessing Exchange more secure via their BigIP.

