Error accessing SQL Server when 3rd guest starts

[Linux-RISC]

Hi all, I'm using this architecture:

- host: Debian 9.11, VirtualBox 55.2.34r133893 headless, phpVirtualBox as administration platform
- guests:
1. Windows 2003 as terminal server of an old Win32 application
2. Windows 2012 as server of a SQL Server application
3. Debian 10, minimal installation without GUI, as Linux services server

Machines 1 and 2 are working Ok, but when the 3rd machine is started the clients using the 2nd machine show connection errors to SQL Server running in that machine.

I thought it was a problem due to the network driver, I changed to VirtIO drivers but the problem persists. When 3rd machine is shutted down, the application connecting to SQL Server in 2nd machine returns to work Ok.

Is there a limit of VM per network interface or hypervisor? What can be happening?

Thanks in advance.

[scottgus1]

Is there a limit of VM per network interface or hypervisor?

The capabilities and limits of the PC hardware and drivers may impose limits, but not from Virtualbox.

when the 3rd machine is started the clients using the 2nd machine show connection errors...When 3rd machine is shutted down, the application connecting to SQL Server in 2nd machine returns to work Ok.

Check IP address, OS network name, Virtualbox guest network card MAC address.

Virtualbox is working, and something network-related in the 3rd guest OS or settings is duplicating a setting in the 2nd guest. Same thing happens in physical PCs.

[Linux-RISC]

Check IP address, OS network name, Virtualbox guest network card MAC address.

Checked, and everything is different

Virtualbox is working, and something network-related in the 3rd guest OS or settings is duplicating a setting in the 2nd guest. Same thing happens in physical PCs.

I agree, but I couldn't find where the network-related problem is.

[scottgus1]

Post, as text in

Code: Select all

 tags, an 'ipconfig /all' from each Windows guest, and an 'ifconfig' or 'ip' from the Linux guest and host.

Also, zip and post each guest's .vbox file, found in the guest's folders. Put them all in the same zip.

When all three guests are running, can you ping from the host and each guest to all the other guests and the host?

Also check that there might be a port overlap between the SQL services and the Debian Linux services?