How do I determine if a port is open on a Windows server

Question

I m trying to install a site under an alternative port on a server  but the port may be closed by a firewall  Is there a way to ping out or in  on a specific port  to see if it is open

User · Answer

On Windows Server you can use  netstat -an   where    Contains  Yourport

User · Answer

Another utility that I found and is good and small as well  is PortQry Command Line Port Scanner version 2 0   You can ping a server and a port and it will tell you the state of the port  There is a command-line utility and a UI for it

User · Answer

Do you want a tool for doing it   There is a website at http   www canyouseeme org    Otherwise  you need some other server to call you back to see if a port is open

User · Answer

Assuming that it s a TCP  rather than UDP  port that you re trying to use    On the server itself  use netstat -an to check to see which ports are listening  From outside  just use telnet host port  or telnet host port on Unix systems  to see if the connection is refused  accepted  or timeouts    On that latter test  then in general    connection refused means that nothing is running on that port accepted means that something is running on that port timeout means that a firewall is blocking access   On Windows nbsp 7 or Windows nbsp Vista the default option  telnet  is not recognized as an internal or external command  operable program or batch file  To solve this  just enable it  Click  Start    rarr  Control Panel  rarr  Programs  rarr  Turn Windows Features on or off  In the list  scroll down and select Telnet Client and click OK

User · Answer

Here is what worked for me    Open a command prompt Type telnet Microsoft Telnet open  lt host name or IP address  lt space  lt port    It will confirm whether the port is opened

User · Answer

Assuming that it s a TCP  rather than UDP  port that you re trying to use    On the server itself  use netstat -an to check to see which ports are listening  From outside  just use telnet host port  or telnet host port on Unix systems  to see if the connection is refused  accepted  or timeouts    On that latter test  then in general    connection refused means that nothing is running on that port accepted means that something is running on that port timeout means that a firewall is blocking access   On Windows nbsp 7 or Windows nbsp Vista the default option  telnet  is not recognized as an internal or external command  operable program or batch file  To solve this  just enable it  Click  Start    rarr  Control Panel  rarr  Programs  rarr  Turn Windows Features on or off  In the list  scroll down and select Telnet Client and click OK

User · Answer

Another option is tcping   For example   tcping host port

User · Answer

I did like that   netstat -an   find  8080     from telnet  telnet 192 168 100 132 8080   And just make sure that the firewall is off on that machine

User · Answer

On Windows Server you can use  netstat -an   where    Contains  Yourport

User · Answer

Assuming that it s a TCP  rather than UDP  port that you re trying to use    On the server itself  use netstat -an to check to see which ports are listening  From outside  just use telnet host port  or telnet host port on Unix systems  to see if the connection is refused  accepted  or timeouts    On that latter test  then in general    connection refused means that nothing is running on that port accepted means that something is running on that port timeout means that a firewall is blocking access   On Windows nbsp 7 or Windows nbsp Vista the default option  telnet  is not recognized as an internal or external command  operable program or batch file  To solve this  just enable it  Click  Start    rarr  Control Panel  rarr  Programs  rarr  Turn Windows Features on or off  In the list  scroll down and select Telnet Client and click OK

User · Answer

Here is what worked for me    Open a command prompt Type telnet Microsoft Telnet open  lt host name or IP address  lt space  lt port    It will confirm whether the port is opened

User · Answer

On a Windows machine you can use PortQry from Microsoft to check whether an application is already listening on a specific port using the following command   portqry -n 11 22 33 44 -p tcp -e 80

User · Answer

If telnet is not available  download PuTTY  It is a far superior Telnet  SSH  etc  client and will be useful in many situations  not just this one  especially if you are administering a server

User · Answer

I did like that   netstat -an   find  8080     from telnet  telnet 192 168 100 132 8080   And just make sure that the firewall is off on that machine

User · Answer

PsPing from Sysinternals is also very good

User · Answer

If you re checking from the outside  not from the server itself  and you don t want to bother installing telnet  as it doesn t come with the last versions of Windows  or any other software  then you have native PowerShell   Test-NetConnection -Port 800 -ComputerName 192 168 0 1 -InformationLevel Detailed    Unfortunately this only works with PowerShell 4 0 or newer  To check your PowerShell version  type  PSVersionTable    PS  Note  these days there are some claims on the twittersphere that hint that this answer could be improved by mentioning  Test-Connection  from PowerShell Core  or the shortcut  tnc   See https   twitter com david obrien status 1214082339203993600 and help me edit this answer to improve it please      If you have a PSVersion  lt  4 0  you re out of luck  Check this table     Even though you can upgrade your version of PowerShell  by installing the Windows Management Framework 4 0  it didn t do the trick for me  Test-NetConnection cmdlet is still not available

User · Answer

If telnet is not available  download PuTTY  It is a far superior Telnet  SSH  etc  client and will be useful in many situations  not just this one  especially if you are administering a server

User · Answer

On Windows you can use  netstat -na   find  your port    to narrow down the results  You can also filter for LISTENING  ESTABLISHED  TCP and such  Mind it s case-sensitive though

User · Answer

Use this if you want to see all the used and listening ports on a Windows server   netstat -an  find  i  listening    See all open  listening  established ports   netstat -a

User · Answer

On Windows you can use  netstat -na   find  your port    to narrow down the results  You can also filter for LISTENING  ESTABLISHED  TCP and such  Mind it s case-sensitive though

User · Answer

Another option is tcping   For example   tcping host port

User · Answer

On a Windows machine you can use PortQry from Microsoft to check whether an application is already listening on a specific port using the following command   portqry -n 11 22 33 44 -p tcp -e 80

User · Answer

Another utility that I found and is good and small as well  is PortQry Command Line Port Scanner version 2 0   You can ping a server and a port and it will tell you the state of the port  There is a command-line utility and a UI for it

User · Answer

If you re checking from the outside  not from the server itself  and you don t want to bother installing telnet  as it doesn t come with the last versions of Windows  or any other software  then you have native PowerShell   Test-NetConnection -Port 800 -ComputerName 192 168 0 1 -InformationLevel Detailed    Unfortunately this only works with PowerShell 4 0 or newer  To check your PowerShell version  type  PSVersionTable    PS  Note  these days there are some claims on the twittersphere that hint that this answer could be improved by mentioning  Test-Connection  from PowerShell Core  or the shortcut  tnc   See https   twitter com david obrien status 1214082339203993600 and help me edit this answer to improve it please      If you have a PSVersion  lt  4 0  you re out of luck  Check this table     Even though you can upgrade your version of PowerShell  by installing the Windows Management Framework 4 0  it didn t do the trick for me  Test-NetConnection cmdlet is still not available

User · Answer

PsPing from Sysinternals is also very good

User · Answer

Do you want a tool for doing it   There is a website at http   www canyouseeme org    Otherwise  you need some other server to call you back to see if a port is open

User · Answer

Assuming that it s a TCP  rather than UDP  port that you re trying to use    On the server itself  use netstat -an to check to see which ports are listening  From outside  just use telnet host port  or telnet host port on Unix systems  to see if the connection is refused  accepted  or timeouts    On that latter test  then in general    connection refused means that nothing is running on that port accepted means that something is running on that port timeout means that a firewall is blocking access   On Windows nbsp 7 or Windows nbsp Vista the default option  telnet  is not recognized as an internal or external command  operable program or batch file  To solve this  just enable it  Click  Start    rarr  Control Panel  rarr  Programs  rarr  Turn Windows Features on or off  In the list  scroll down and select Telnet Client and click OK

User · Answer

Do you want a tool for doing it   There is a website at http   www canyouseeme org    Otherwise  you need some other server to call you back to see if a port is open

User · Answer

Use this if you want to see all the used and listening ports on a Windows server   netstat -an  find  i  listening    See all open  listening  established ports   netstat -a

User · Answer

Do you want a tool for doing it   There is a website at http   www canyouseeme org    Otherwise  you need some other server to call you back to see if a port is open

[windows-server-2003] How do I determine if a port is open on a Windows server?

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