Using Test-NetConnection to check connectivity

Jan 7, 2016 · 2 min read · microsoft windows powershell networking ·

A regular ping command is great for checking if Host A can see Host B, but what if we want to go a bit deeper- for example check if a web server is contactable on port 80 and 443? The PowerShell cmdlet Test-NetConnection is a great tool for doing this.

It’s become a key part of my troubleshooting toolkit- is the server contactable? Is there a firewall blocking the traffic? Is the web server service running? Test-NetConnection gives us a simple yes/no and some other useful information too.

Examples:

A working connection to port 80 (HTTP) on the server

 1PS C:\> Test-NetConnection -ComputerName Server1.MyDomain.Com -Port 80
 2
 3ComputerName : Server1.MyDomain.Com
 4RemoteAddress : 10.0.0.34
 5RemotePort : 80
 6InterfaceAlias : Local Area Connection
 7SourceAddress : 10.0.0.17
 8PingSucceeded : True
 9PingReplyDetails (RTT) : 14 ms
10TcpTestSucceeded : True

A failed connection to port 443 (HTTPS) on the same server

 1PS C:\> Test-NetConnection -ComputerName Server1.MyDomain.Com -Port 443
 2WARNING: TCP connect to Server1.MyDomain.Com:443 failed
 3
 4ComputerName : Server1.MyDomain.Com
 5RemoteAddress : 10.0.0.34
 6RemotePort : 443
 7InterfaceAlias : Local Area Connection
 8SourceAddress : 10.0.0.17
 9PingSucceeded : True
10PingReplyDetails (RTT) : 22 ms
11TcpTestSucceeded : False

From this we can quickly and easily establish that whilst communication with the server is possible on port 80, traffic on port 443 is not being received- the first things I would check here would be that the webserver service is running correctly, configured to accept HTTPS traffic, and not being blocked the local firewall on the server.