How do I get client IP address in ASP.NET CORE?
Some fallback logic can be added to handle the presence of a Load Balancer.
Also, through inspection, the X-Forwarded-For
header happens to be set anyway even without a Load Balancer (possibly because of additional Kestrel layer?):
public string GetRequestIP(bool tryUseXForwardHeader = true)
{
string ip = null;
// todo support new "Forwarded" header (2014) https://en.wikipedia.org/wiki/X-Forwarded-For
// X-Forwarded-For (csv list): Using the First entry in the list seems to work
// for 99% of cases however it has been suggested that a better (although tedious)
// approach might be to read each IP from right to left and use the first public IP.
// http://stackoverflow.com/a/43554000/538763
//
if (tryUseXForwardHeader)
ip = GetHeaderValueAs<string>("X-Forwarded-For").SplitCsv().FirstOrDefault();
// RemoteIpAddress is always null in DNX RC1 Update1 (bug).
if (ip.IsNullOrWhitespace() && _httpContextAccessor.HttpContext?.Connection?.RemoteIpAddress != null)
ip = _httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();
if (ip.IsNullOrWhitespace())
ip = GetHeaderValueAs<string>("REMOTE_ADDR");
// _httpContextAccessor.HttpContext?.Request?.Host this is the local host.
if (ip.IsNullOrWhitespace())
throw new Exception("Unable to determine caller's IP.");
return ip;
}
public T GetHeaderValueAs<T>(string headerName)
{
StringValues values;
if (_httpContextAccessor.HttpContext?.Request?.Headers?.TryGetValue(headerName, out values) ?? false)
{
string rawValues = values.ToString(); // writes out as Csv when there are multiple.
if (!rawValues.IsNullOrWhitespace())
return (T)Convert.ChangeType(values.ToString(), typeof(T));
}
return default(T);
}
public static List<string> SplitCsv(this string csvList, bool nullOrWhitespaceInputReturnsNull = false)
{
if (string.IsNullOrWhiteSpace(csvList))
return nullOrWhitespaceInputReturnsNull ? null : new List<string>();
return csvList
.TrimEnd(',')
.Split(',')
.AsEnumerable<string>()
.Select(s => s.Trim())
.ToList();
}
public static bool IsNullOrWhitespace(this string s)
{
return String.IsNullOrWhiteSpace(s);
}
Assumes _httpContextAccessor
was provided through DI.
The API has been updated. Not sure when it changed but according to Damien Edwards in late December, you can now do this:
var remoteIpAddress = request.HttpContext.Connection.RemoteIpAddress;
In project.json add a dependency to:
"Microsoft.AspNetCore.HttpOverrides": "2.2.0"
In Startup.cs
, in the Configure()
method add:
app.UseForwardedHeaders(new ForwardedHeadersOptions
{
ForwardedHeaders = ForwardedHeaders.XForwardedFor |
ForwardedHeaders.XForwardedProto
});
And, of course:
using Microsoft.AspNetCore.HttpOverrides;
Then, I could get the ip by using:
Request.HttpContext.Connection.RemoteIpAddress
In my case, when debugging in VS I got always IpV6 localhost, but when deployed on an IIS I got always the remote IP.
Some useful links: How do I get client IP address in ASP.NET CORE? and RemoteIpAddress is always null
The ::1
is maybe because of:
Connections termination at IIS, which then forwards to Kestrel, the v.next web server, so connections to the web server are indeed from localhost. (https://stackoverflow.com/a/35442401/5326387)
Edit 12/2020: Thanks to SolidSnake: as of Dec 2020 the latest version is 2.2.0
Edit 06/2021: Thanks to Hakan Fıstık: In .NET 5 the namespace is Microsoft.AspNetCore.Builder