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Test for open ports from using Telnet, Portqry.exe or Powershell

December 18, 2018 by Paulie 1 Comment

Checking if a port is open interactively or through a script is quite a common operation for any administrator. There are all sorts of reasons you might want to do this:

Check if a web server is down.
Check if a printer is working.
Check if a firewall is blocking a port.
Check if an SMTP Server is reachable etc.

You can test for open ports using a variety of different tools all of which have their pros and cons.

Telnet
Portqry.exe
Powershell Test-NetConnection

Using Telnet to test for open ports

This is the probably the most common method to check for an open port. Unfortunately Microsoft stopped including the telnet client by default on Windows Server, so you will need to install the telnet client first if it is not already installed.

The general syntax is: “telnet host portnumber”. If you do not specify a port number it will attempt to connect to the host on port 23, which is the standard telnet port.

Telnet example to Check an SMTP Server

You can check if a server has SMTP server running and available by using telnet to connect to port 25. In this example I am testing connection to my own mail server which is on Office 365:

telnet tachytelic-net.mail.protection.outlook.com 25

If you can successfully connect you will see a response from the mail server:
You can even manually send an email message directly to the SMTP server interactively using telnet.

Telnet example to check a Web Server

You can connect to a Web server on port 80 to check that it is serving requests:

telnet www.tachytelic.net 80

In the case of a webserver you will probably just receive a blinking cursor while it waits for some input, but this does indicate a successful connection and that the port is open. You can take it a step further by issuing a HTTP Request with telnet, for example:

GET /2018/12/email-vbscript-vba-office-365/ HTTP/1.1
host: www.tachytelic.net

I get a response from the server issuing a 301 redirect sending me to the HTTPs version of the same page:

Telnet example to check a printer

You can check if a printer is working (and actually print to it) using telnet. Many printers will have port 9100 open for HP Jetdirect style printing. My printer is on 192.168.250.34. So if I run the telnet command:

telnet 192.168.250.34 9100

I will come to a flashing cursor while the print server embedded in my HP Printer waits for input. If I type “This is a test” and then quit telnet it prints a page with those words on it.

Advantages of using telnet

Quick and easy to do a port test
Interactive so you can do more extensive testing of certain services.
More or less available on any operating system.

Disadvantages of using telnet

It is interactive, so it is not suitable for automated tests.
Not installed by default on recent versions of Windows. But easy to install, follow these instructions.
Not useful for check UDP ports.

Using Portqry.exe to test for open ports

Portqry.exe is an old tool but still works well and has extensive options for port testing. It’s much easier to use within scripts or automated checks. It can be used to check multiple ports in a single command and makes it easy to check UDP ports as well as TCP ports.

Example Portqry command to check a single port on a web server

In this example I am checking port 443 (https) of this blog:

portqry -n www.tachytelic.net -p tcp -e 443

Here you can see the test was successful:

Example Portqry to check multiple ports on a Web server

This example shows how to use Portqry to test multiple ports at the same time, in this case ports 80 and 443:

portqry -n www.tachytelic.net -p tcp -o 80,443

Again, the results are good:

Example Portqry to check an SMTP Server

Portqry is aware of some types of applications and can show you additional information returned from the server, SMTP is a good example:

portqry -n tachytelic-net.mail.protection.outlook.com -p tcp -e 25

As you can see from the screenshot, Portqry.exe returns the initial response from the SMTP Server:

Portqry.exe is excellent for scripting because of the vast number of options and that it can operate in quiet mode where it will simply return a status code, which is exactly what you would want if you were building this into a script. Portqry.exe has many options so it is well worth reading the documentation.

Advantages of using Portqry.exe

Easy to use.
Many options for checking both TCP and UDP ports.
Quiet mode is excellent for scripting.
Very fast.

Disadvantages of using Portqry.exe

It is not installed by default.
It is old software, but still works perfectly on recent operating systems.

Using Powershell Test-NetConnection to test for open ports

You can also use Powershell to test for open ports and this is a great option because it works well both interactively and for usage within a script. It’s built in to recent versions of Powershell and it is very easy to use.

Example Test-NetConnection Powershell to check a single port on a Web server

Again, this code shows how to test port 443 of this blog using Powershell:

Test-NetConnection -ComputerName www.tachytelic.net -Port 443

Here is the output of the successful test:

Example Test-NetConnection Powershell to check an SMTP Server

Test-NetConnection -ComputerName tachytelic-net.mail.protection.outlook.com -Port 25

And the successful output:

Advantages of using Test-NetConnection

Built in to recent versions of Windows
Great for scripting if you are already using Powershell
Quick and Easy

Disadvantages of using Test-NetConnection

Not available on all versions of Windows by default.
Only available via Powershell – which isn’t a problem, but might not fit in with some of your existing scripts.

Use CDO to send email from VBScript or VBA through Office 365

December 16, 2018 by Paulie Leave a Comment

Sending email via VBScript or VBA using CDO is easy to do, but the correct configuration to relay through Office 365 is confusing to say the least and it took me me a while to find the correct settings.

I knew from configuring other devices and software that the preferred way to setup SMTP to relay to Office 365 was to use TLS on port 587. The problem is that officially CDO does not support TLS, but unofficially it does. So I tried in vain to develop some code that would send email via smtp.office365.com using TLS and always came up with the following error:

The server rejected the sender address. The server response was: 530 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM

So clearly the TLS support in CDO is not sufficient to be able to work with the Office 365 SMTP Server. The trick is not to use TLS at all, but to use SSL instead on port 25 instead, which seems to work fine:

VBScript to Send Email via Office 365 (smtp.office365.com)

This is just quick sample code to get you on the right path:

Dim objMessage, objConfig, Fields
Set objMessage = CreateObject("CDO.Message") 
Set objConfig = CreateObject("CDO.Configuration")
Set Fields = objConfig.Fields
With Fields
  .Item ("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2 
  .Item ("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "smtp.office365.com"
  .Item ("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25
  .Item ("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1
  .Item ("http://schemas.microsoft.com/cdo/configuration/sendusername") = "[email protected]"
  .Item ("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "Office365Password"
  '.Item("http://schemas.microsoft.com/cdo/configuration/sendtls") = True
  .Item("http://schemas.microsoft.com/cdo/configuration/smtpusessl") = True
  .Update
End With
Set objMessage.Configuration = objConfig

With objMessage
  .Subject = "Test Message"
  .From = "[email protected]"
  .To = "[email protected]"
  .HTMLBody = "Test Mesage"
end With
objMessage.Send

VBA to send email via Office 365 (smtp.office365.com)

The code for VBA is almost the same as VBScript and I tested it using Excel 2016 without any problems at all. But first you need to add a reference to your project:

In the Office VBA Code Editor go to Tools, and then References:
In the References dialog box add a reference to the “Microsoft CDO for Windows 2000 Library”:
Use the following sample code….

Sub Office365_Email_Test()
    Dim objMessage, objConfig, fields
    Set objMessage = New CDO.Message
    Set objConfig = New CDO.Configuration
    Set fields = objConfig.fields
    With fields
        .Item("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2
        .Item("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "smtp.office365.com"
        .Item("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25
        .Item("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1
        .Item("http://schemas.microsoft.com/cdo/configuration/sendusername") = "[email protected]"
        .Item("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "Office365Password"
        '.Item("http://schemas.microsoft.com/cdo/configuration/sendtls") = True
        .Item("http://schemas.microsoft.com/cdo/configuration/smtpusessl") = True
        .Update
    End With
    Set objMessage.Configuration = objConfig
    
    With objMessage
        .Subject = "Test Message"
        .From = "[email protected]"
        .To = "[email protected]"
        .HTMLBody = "Test Message"
    End With
    objMessage.Send
End Sub

A few things to note:

The account that you use must have at least an Exchange Online license.
You will only be able to send from addresses that account has send as permission for or an alias of that account.
It would probably be a good idea to use an account dedicated for sending SMTP because the password is being stored in clear text.
Your Firewall or your ISPs Firewall may block outbound port 25.
I’ve left the code for TLS in-place above but commented out, in case anyone else wants to have a play with it.

I hope this helps, I spent ages trying to relay through Office 365 over TLS with VBA, but SSL works just fine.

How to install Flash Player in Windows Server 2019

December 14, 2018 by Paulie Leave a Comment

Windows Server 2019 does not come with Flash Player installed by default. But it can be installed very easily, here is how to do it:

How to install Flash Player on Windows Server 2019

Copy and paste the below command into a command prompt:

dism /online /add-package /packagepath:"C:\Windows\servicing\Packages\Adobe-Flash-For-Windows-Package~31bf3856ad364e35~amd64~~10.0.17763.1.mum"

You should get output like the following if you had a successful installation:
You can verify if the installation was successful by visiting:
https://helpx.adobe.com/flash-player.html
you should be able to see that Flash Player shows as installed and detected as per the following:

If you need to install Flash Player on other versions of Windows Server, instructions are here:

How to comment a block of code in the Office VBA Editor

November 28, 2018 by Paulie Leave a Comment

Being able to comment a block of code is a standard operation in any IDE, but for some reason the Microsoft Office VBA Editor does not include that functionality by default. However, the functionality is there and waiting to be used, it’s just hidden in the “Edit” toolbar which is not visible be default.

How to add the comment & uncomment buttons to the Office VBA Editor

Open the VBA Editor (Alt + F11).
Right click anywhere on the toolbar.
Select the “Edit” Toolbar.
You will now be able to quickly and easily comment a block of code (or uncomment) using these new buttons on your toolbar:
Done!

Here is a short video showing how to enable the edit toolbar to get access to the comment and uncomment buttons:

Hope this helps!

How to install telnet client on Windows Server 2019, 2016 or 2012

November 28, 2018 by Paulie 1 Comment

Windows Server does not install Telnet by default, it’s such a tiny executable I cannot understand why it is left out by default. however it is very easy to enable telnet on Windows Server 2016 or 2012. If you do not have telnet installed you will see this message from the command line:

Image showing telnet not available in Windows Server — Telnet is not recognized as an internal or external command.

Install Telnet Client on Windows Server 2019, 2016 or 2012 using the command line

The command line is the quickest way of installing the telnet client, very simply just type:

dism /online /Enable-Feature /FeatureName:TelnetClient

Install Telnet Client on Windows Server 2016 using Server Manager

You can use Server Manager to install the telnet client, but it is a much longer process than doing it via the command line, here is a short video of the correct options to select.

Check that Telnet is installed

To check if your installation was successful, just go into a command prompt and type “telnet” and you should come to the interactive telnet prompt, like this:

Check Ports with Telnet

Now that you have got telnet installed, you can use it to test open ports ports and connect to remote machines.

How to change network profile on Windows Server 2016

November 27, 2018 by Paulie Leave a Comment

Under some circumstances Windows Server will automatically select a network profile for you which does not match your needs. It’s not very clear how to change it between public and private within the network and sharing center. In my opinion the easiest way is to use Windows Powershell to change network profile on Windows Server 2016.

Here is how to change the profile from public to private for your network connection on Windows Server 2016. There are several methods of doing this but I find the GUI method to be very unclear. So here I am going to document how to change the network profile using Powershell.

How to change network profile on Windows Server 2016 to Private using Powershell

Open Powershell
Type Get-NetConnectionProfile
If you have only one network connection you can change the profile to private by typing:
```
Get-NetConnectionProfile | Set-NetConnectionProfile -NetworkCategory Private
```
If you have multiple network interfaces and would like to change a specific adapter use the Interface Index Property like this:
```
Set-NetConnectionProfile -InterfaceIndex 3 -NetworkCategory Private
```
You can then verify the change has taken place by running Get-NetConnectionProfile again:

Obviously you can also use this method to switch back to a public profile:

Switch to public network profile

Set-NetConnectionProfile -InterfaceIndex 3 -NetworkCategory Public

Switch to domain network profile

You cannot use this method to switch to a domain profile because that happens automatically.