Q&A: Does Silverline append additional IP addresses in the X-Forwarded-For?

Question

• Does Silverline append more IP address in the X-Forwarded-For?

Environment

• Silverline WAF

• Proxy/Proxies

  • Insert XFF

Answer

• Yes, by having X-Forwarded-For enabled, Silverline appends the last Client IP from the request.
  
  • Example: “X-Forwarded-For: 192.168.1.100, 192.168.1.200”

• If your web application is coded to simply grab the first or leftmost IP address in the list, this can lead to a spoofing attack, to only have one IP address we can implement an iRule to rewrite Client IP with the Last Client IP: Q&A: Is it Possible to Configure/Forward Only the Last Client IP in the X-Forwarded-For (XFF) Header?

Related Content

• Q&A: Is it Possible to Configure/Forward Only the Last Client IP in the X-Forwarded-For (XFF) Header?
• How to Configure Advanced (Proxy) - where to configure X-forwarded for