C# / .NET core: Get Remote IP Address with Proxy / CDN Support

HttpContext_RemoteIPAddress.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading.Tasks;

using Microsoft.AspNetCore.Http;

namespace HttpContext_RemoteIPAddress
{        
    public static class HttpContextExtensions
    {
        /// <summary>
        /// Get remote ip address, optionally allowing for x-forwarded-for header check
        /// </summary>
        /// <param name="context">Http context</param>
        /// <param name="allowForwarded">Whether to allow x-forwarded-for header check</param>
        /// <returns>IPAddress</returns>
        public static IPAddress GetRemoteIPAddress(this HttpContext context, bool allowForwarded = true)
        {
            if (allowForwarded)
            {
                // if you are allowing these forward headers, please ensure you are restricting context.Connection.RemoteIpAddress
                // to cloud flare ips: https://www.cloudflare.com/ips/
                string header = (context.Request.Headers["CF-Connecting-IP"].FirstOrDefault() ?? context.Request.Headers["X-Forwarded-For"].FirstOrDefault());
                if (IPAddress.TryParse(header, out IPAddress ip))
                {
                    return ip;
                }
            }
            return context.Connection.RemoteIpAddress;
        }
    }
}

Thanks for the gist. You can use this to also parse ip addresses with port information.

if (IPEndPoint.TryParse(header, out IPEndPoint ip))
{
    return ip.Address;
}

Thanks