we have multiple Netgear switches (3300, 5300, 4300... - current firmware) and on most of them we have the same behavior.
Let's say we have two networks. One is the main office network 192.168.1.0/24 - the second is the management network 192.168.10.0/24. Management network runs as VLAN 10 on the switches, the office network runs on the "default" VLAN 1 on the Netgear devices.
Now we define an IP Address in the management network (no DHCP there) for the Management Interface of the switch. We configure the VLAN, set the IP address, and can connect. But as soon as we connect the switch to both networks, we get a secondary IP address in the office network (we have a DHCP server here). I don't want these addresses to exist, once because they are unnecessarily using DHCP leases, and also because I don't want the swtiches to be availble in the office network.
How can I tell my switch not to enable VLAN 1 as additional management interface?
I asked this in the Netgear forum and got a few responses that I did not really understand completly (not a networking expert), but if I interpreted the responses correctly, this is by design and not easy to disable, which is in my opinion a stupid desing choice from a security perspective - as soon as I use the preconfigured VLAN 1 on the switch, I will always have access to the switch from this network.
EDIT: Okay now I finaly found the place where I see this IP and could maybe configure it: I checked the config file for any occurence of "DHCP" and found this section:
interface vlan 1 routing ip address dhcp exit
In the web config I can go to "Routing", under "Routing Table" I can finaly see this IP. And under "Rounting - VLAN - VLAN Routing Configuration" I see an entry for both VLANs with the corresponding addresses. Now I am not sure what happens if I just delete the VLAN 1, but I have two switches on my desk I am preparing at the moment - so I will test this during the day.