Authorize.net Direct post showing x_client_ip 127.0.0.1 with Varnish cache

[treii28]

On a magento 2 server configured as recommended in the Magento website documentation behind a Varnish->nginx cache using the default.vcl spit out of Magento, when I try to run a payment through authorize.net, it sends x_client_ip as 127.0.0.1

Preconditions

Magento v2.2.2
apache2 v2.4.18
varnishd v4.1.1
nginx v1.10.3
php7.0

Steps to reproduce

Generated a live payment request using the direct post support in Magento2 for Authorize.net. Checked the content in the browser's Network inspect window for transact.dll (at authorize)

Expected result

Presumably it reads the HTTP server variable REMOTE_ADDR
I'm guessing it might need to read the value of X-Forwarded-For when it exists because the server is running behind a cache.

Actual result

in the Network tab of the browser for transact.dll, I can see in the outgoing parameters x_client_ip is 127.0.0.1

[treii28]

This may be related to #7227 but is more specific to the direct post. Currently, Authorize.net is not sending back a relay response (no record of the incoming POST in any of the server logs) but Authorize is reporting a timeout waiting for a response. I'm trying to track down anything on our end that might cause that when I noticed the localhost IP in the outgoing data. (my worry is they may not be sending back the response due to the reported client_ip looking suspicious)

Addendum: this turned out not to be the reason authorize.net was not responding, but it would still be nice to have the correct information displayed for logging purposes since that information (including the client ip) is relayed back from authorize.net to be logged locally.
I confirmed the forwarded-for headers are properly being passed through by both nginx on the front end and by varnish by modifying the apache log to show [forwarded addresses] remote_addr at the start of each entry which shows exactly what I would expect.

[engcom-backlog-nickolas]

Hello @treii28, thank you for your report.
We've acknowledged the issue and added to our backlog.

[magento-engcom-team]

@treii28, thank you for your report.

Unfortunately, we are archiving this ticket now as it did not get much attention from both Magento Community and Core developers for an extended period. This is done in an effort to create a quality, community-driven backlog which will allow us to allocate the required attention more easily.

Please feel free to comment, reopen or create new ticket according to the Issue reporting guidelines
if you are still facing this issue on the latest 2.3-develop branch. Thank you for collaboration.