I receive a '404' error when I make any API call. I am trying to learn how to make API requests. I know practically nothing about it, so I imagine I am doing several things wrong. I am using the HTTP API guide, provided in PRTG Setup.

I am using the following Powershell request, on the server that hosts the probe:

Invoke-WebRequest "http://myserver/api/getsensordetails.xml?id=5025&username=myuser&passhash=0987654321"

The user is an administrator. The server is within our LAN, although we access it via 'https'. If I make the request with https://... I receive a "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel" error.

Any help is appreciated. Cheers.

Article Comments

If you use HTTPS to connect to your PRTG server, you must also use HTTPS in the API call.

How are you using the API call, is it in a VB or C# programm?


May, 2015 - Permalink

I am just running it from the PowerShell console. I am trying to figure out how it works. If I use HTTPS in the API call I receive the error regarding trust relationships.


May, 2015 - Permalink

Execute this beforehand: 

# Ignore invalid SSL certs in a webrequest
[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}

The PowerShell instance will then ignore certificates that are invalid for some reason.


Jun, 2015 - Permalink 
[13]: C:\ 

> [System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}

[14]: C:\ 

> Invoke-WebRequest "https://xxxxx/api/getsensordetails.xml?id=5025&username=myuser&passhash=0987654321"
Invoke-WebRequest : The underlying connection was closed: An unexpected error occurred on a send.
At line:1 char:1
+ Invoke-WebRequest "https://xxxxxx/api/getsensordetails.xml?id=5025&u ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand

Jun, 2015 - Permalink

Seems like my line isn't sufficient somehow. How about this one: 

Add-Type @"
    using System.Net;
    using System.Security.Cryptography.X509Certificates;
    public class TrustAllCertsPolicy : ICertificatePolicy {
        public bool CheckValidationResult(
            ServicePoint srvPoint, X509Certificate certificate,
            WebRequest request, int certificateProblem) {
            return true;
        }
    }
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy

$result = Invoke-WebRequest -Uri "https://IpAddress/resource"

Jun, 2015 - Permalink

I found that solution, as well. I tried it with similar results. Here is the fiddler trace: 

Session #12: The remote server (myserver) presented a certificate that did not validate, due to RemoteCertificateNameMismatch, RemoteCertificateChainErrors.

0 - A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.


SUBJECT: CN=PRTG Demo Certificate, O=PRTG Demo Certificate
ISSUER: CN=PRTG Demo Certificate, O=PRTG Demo Certificate
EXPIRES: 7/6/2023 6:15:05 AM

(This warning can be disabled by clicking Tools | Fiddler Options.)

I will work through the ssl certificate kb article, to try and resolve this.


Jun, 2015 - Permalink

Okay, let me know if you need further help :)


Jun, 2015 - Permalink