How to view the original client IP on my IIS server?

[SimonM]

Hello, currently I am using Cloudflare’s free plan, but I only see Cloudflare’s IP in my website’s log.
I would like to know how to see the original client IP.

1. Do I need to upgrade to the Business Plan to see it?
2. Also, if I upgrade to the Business Plan, will I be able to see the original IP of previous customers, such as the IP on 2023/1/1?

Thank you!

[Chaika]

You do not need to upgrade! (nor would upgrading help with this)

You just need to configure your web server to restore visitor IPs. The original client’s ip is contained in the CF-Connecting-IP Header, you just need to configure your web server to use that.
There are instructions here on how to configure your web server to do that for popular web servers, including for IIS.

Restoring original visitor IPs · Cloudflare Support docs

[SimonM]

Hi Chaika,

As I didn’t configure the related settings on IIS before,
if I set it up now, will I be able to see the original IP address of previous clients?
(maybe 2 weeks ago client’s IP)

[Chaika]

No, if you set it up now it would start logging the correct User IP’s from this point on.

I don’t believe there is going to be any way for you to retroactively find old IPs, unless you were logging/storing all of the headers (including cf-connecting-ip). The IPs you see without Restoring the original visitor IPs are Cloudflare IPs, which are shared/used by more than one user request.

[SimonM]

Thank you for replied.
appreciated.