Which expression would configure a Citrix Gateway to accept incoming connections initiated exclusively from web browsing sessions (not Citrix Receiver)?

• A. REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver
• B. REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver
• C. REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver AND REQ.HTTP.HEADER Host CONTAINS example.com
• D. REQ.HTTP.HEADER User-Agent NOTREGEX CitrixReceiver

Answer: (A)

This question tests filtering based on the User-Agent header to separate browser-based web sessions from Citrix Receiver sessions. You want incoming connections that come from regular web browsers and exclude any that identify as Citrix Receiver. The expression REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver does exactly that: it allows requests whose User-Agent does not include the CitrixReceiver string, so only web browser sessions are accepted. The other options either look for the opposite condition (requiring CitrixReceiver in the User-Agent, which would accept Receiver-based connections), add an unnecessary host constraint (which narrows the scope without addressing the web-vs-receiver distinction), or use a NOTREGEX test that is less explicit and could behave inconsistently depending on how the client User-Agent is formed. Therefore, this expression best enforces acceptance of web browser-initiated connections only.