If your A10 is configured to append the client IP (the default), the header becomes: X-Forwarded-For: 127.0.0.1, 203.0.113.5
insert-client-ip-header replace
on the A10 or the backend server to confirm the header is present in the POST data. Web Server Logs: a10 x-forwarded-for
Unlike XFF, which is HTTP-specific, PROXY Protocol prepends a binary header at the transport layer. It preserves the original client IP for any protocol—HTTP, HTTPS, SMTP, or raw TCP. If your backend server supports PROXY Protocol (e.g., HAProxy, Nginx, Apache 2.4.30+), this is a more robust solution than XFF. If your A10 is configured to append the