Ok - so this is not exactly PC hardware. Bear with me... Since my old switch got maxed out I purchased a second hand HP Switch: 1820-48G (J9981A). This is a managed switch with 48 channels (and 4 Fiber Trx slots). This switch has the default address of 192.168.1.1 when nothing else is using this address. If it is occupied, it choses another free one in the DHCP space. Since 192.168.1.1 is used by the ISP modem, and the 192.168.1.2 by my hardware firewall, I wanted to use 192.168.1.3. However... Setting the switch to this address causes either the internet traffic to be blocked. Nothing gets in or out. The address as such is not reachable. (mask is 255.255.255.0) This happends regardless of the switch is configured for DHCP or Static. Resetting it to factory settings make severything work as a charm but scanning the IP address range, the DHCP assigned switch address is nowhere to be found. I have previously done similar thing with an old Zyxel 1GBit managed switch and that particular switch could be configured like this. I downloaded IPScan tool. It has a collector select function that can be used for probing the network. The default settings finds my ISP Modem, the firewall, the computer that I am using right now, my network attached printer and my TV. Any special setting that I should use?
Download configuration manual from HP and search on youtube for tuto i've found many. seems to be easy to configure
I did download the manual of course. It describes the network configuration options, but fails to mention that apart from the netmask 255.255.255.0 (which is already typed in the form field), also the DNS needs to be added, in my case 192.168.1.1 After defining this everything worked like a charm. I also found out that the firmware had been updated many times since HP put the switch on the market so I took the time to flash the latest release.