PuTTY to local console connection using a pipe with cOS Core under Hyper-V

Last modified on 19 Apr, 2023. Revision 5
This article details the steps needed to use a named Pipe in Microsoft Hyper-V to connect a serial puTTY connection to the local console of a virtual cOS Core firewall running under Hyper-V.
Up to date for
cOS Core 14.00.09
Microsoft Hyper-V 10.xx.
Supported since
cOS Core 12.00.xx
Status OK
Peter Nilsson


When using a virtual cOS Core firewall it may sometimes be useful to gain access to the firewall’s local console. Note that in 32 bit cOS Core local console access never times-out and in 64 bit cOS Core it is possible to disable the authentication requirement on the local console, meaning that it will also then never time-out. This can be useful for troubleshooting purposes if all output on the local console is to be logged to a file over a longer time period.


Step-1: Power off the firewall (as we cannot change hardware settings while it is powered on)

Step-2: Activate a named Pipe on the serial COM port on the firewall virtual machine in Hyper-V, as shown below.

Step-3: Start the firewall again.

Step-4: Start PuTTY and run it as administrator (Note: This is important!)

Step-5: Add the named pipe path to puTTY’s serial console, as shown below.

Note: The path value may differ depending on where you connect from.

All done! We can now get cOS Core local console output from Hyper-V using PuTTY. As shown in the puTTY screenshot below, activate logging of all console/session output (1) to a chosen file location (2). Do not forget to turn off puTTY logging once the data gathering is complete.

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