HAProxy community

Add custom TLV to proxy protocol sent to backend servers?


Is there a way to make use of the extensibility of the PROXY protocol and to add a TLV-field to the PROXY variables sent to the backend servers? I would like to i.e. generate a random value per request, add that to the access log and also forward this very value to the backend service (speaking / understanding PROXYv2 of cause). This way it’s possible to correlate between the incoming request handled and distributed by HAProxy and the corresponding request which is logged on the backend server.

  1. Are there config options anywhere?
  2. I did not find any LUA API bindings to access the PROXY protocol values.

Thanks in advance,



I think (both) your threads would be better suited for the mailing list. A whole lot of advanced users are there, which unfortunately is not the case for this discourse instance here.

You don’t have to subscribe, just send your post to:

and ask for a Reply-All.


Thanks for the hint … just subscribed and posted to the ML.