How to pass remote server ip as header in haproxy tcp tunnel with accept-proxy enabled?

Josh

10/21/23, 3:17 PM

I need to a variable for haproxy that is the actual remote ip while still using accept-proxy, like http-response set-header Upstream-Server %[req.real_ip]. %[src] does not work and sends the client ip from the proxy protocol if accept-proxy is active.

I have a setup like this:

haproxy load balancers
haproxy ddos protection servers
nginx proxying to PHP web applications

1 accepts public Internet HTTP/S connections and mode tcp forwards them.
2 accept-proxy these connections, terminates ssl crt, and then applies anti-bot logic.
3 is the final destination and web application.

This is a pretty complicated setup so occasionally there are hiccups in the configuration which are hard to diagnose because of the number of moving parts. I need nginx to know the IPs of 1 and 2 so it can send that to the actual web application for debugging.

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haproxy

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Server

Josh

10/21/23, 7:10 PM

Very obtuse but this works.

tcp-request must appear before any http-request to not cause warnings. tcp-request connection is the only scope in which src is not changed by the accept-proxy directive in bind. Thus,

frontend http-in
        bind :443 ssl crt /etc/ssl/mycert accept-proxy
        option forwardfor

        tcp-request connection set-var(sess.last_server_ip) src
        http-request add-header X-Forwarding-Frontend %[var(sess.last_server_ip)]

This will add the header X-Forwarding-Frontend with the value of the server that haproxy received the proxy protocol request from. It must be set as a variable this way, because src has a different value in every other context when not as an argument for tcp-request connection.

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