http://www.haproxy.org/download/1.8/doc/proxy-protocol.txt

for reference.

From: Howard Chu <hyc@symas.com>
Date: Wednesday, November 18, 2020 at 8:51 AM
To: Paul B. Henson <henson@acm.org>, openldap-technical@openldap.org <openldap-technical@openldap.org>
Subject: Re: HAProxy protocol support?

Paul B. Henson wrote:
> So management is insisting that we migrate our openLDAP systems from on premise into the cloud <sigh>. Specifically, AWS behind one of their load balancers.
>
> However, we currently rely upon some level of IP address based access control to distinguish between on-campus and off-campus clients. The Amazon load balancers
> do client NAT, so the back end servers have no idea who is connecting at the TCP/IP level.
>
> They do support the haproxy in band protocol for supplying this information from the load balancer to the server, but that requires specific support from the
> server to do. I don't see any such support in openldap or any evidence of past discussion regarding it.
>
> Is this something that would be considered as a possible feature to be included at some point, or something not desired as part of the code base?

Depends on what that feature actually looks like. Feel free to submit a proposal
on the -devel mailing list, including background info on what HAproxy protocol
looks like, and what exact behaviors you want it to provide.

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/