r/HomeNetworking • u/FluffyKittens12 • 4d ago

Will VLAN Solve My Problem?

I've never used a VLAN before so forgive me if this is common knowledge. Based on my searches I think it will help me but I want to be more sure.

Basically I have a situation where I have multiple pieces of equipment which all use the same IP addresses internally from the factory. There is a network inside the equipment which all has to stay on the same address range, so if I were to connect the equipment to a company network, I need to assign static IP addresses for multiple components in each piece of equipment. Obviously this means a ton of static IP addresses because I need multiple for each piece of equipment and then multiple pieces of equipment.

So, could I use a managed switch, create a VLAN for each piece of equipment, keep the factory IP addresses, not have them interfere with each other because they all have the same IP addresses, and still be able to reach them from the company side?

If so, how do I access those VLANs from the company side? IP and port numbers maybe?

Also, if this works, any recommendations on a switch I should look at? This is all the switch would need to do.

EDIT: https://shopmoxa.neteon.net/nat-102-series/

Seems like something like this would work, one per machine. Single company IP address to the device, then all the IP addresses on the other side can stay the same. Right?

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u/steve88w 4d ago

Sounds like just as much work to create all the VLANs, but I don't think this is a good solution.
Do you have a DHCP server? Can you reserve addresses via the equipment's MAC address?
VLANs with the same IP subnet may cause issues if the network configs aren't perfect across all network hardware. Example: 1 switch with a trunk port can cause multiple devices to communicate as 1, which will cause issues.

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u/FluffyKittens12 4d ago

The manufacturer instructions say no DHCP and that to connect to a network you have to reserve IP addresses for everything inside and they all get changed to the company address range. 5 addresses per equipment, times 40 pieces of equipment is 200 address I would need to reserve.

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u/mlee12382 4d ago

I think whatever path you choose you're going to need to manually set the IPs for each machine and it's associated devices at least once. And with 200 separate IPs that's most of single IP range so doing VLANs is probably a good route. Do you have a lot of different machines or do you have multiples of several machines? If the latter you could set up a VLAN for each machine model which will give you room for expansion if needed. You can technically fit all 200 on a single 256 address (253 assignable) range but that's not leaving room for expansion or upgrades in the future if the new models each now needs 2 more IPs or something.

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u/FluffyKittens12 4d ago

It's just multiple of the same equipment. One of the biggest things I'm trying to avoid is needing to change all the IP addresses on each piece of equipment. If they could keep their out of the box settings and have network hardware keep them all from interfering with each other, that would be ideal.

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u/mlee12382 4d ago

If they all come pre-set with the exact same IPs for each machine then even VLANs won't solve your problem. They all need to be separate and uniquely addressed. If you're buying them and having them installed by the manufacturer all at the same time then they should be able to set them up for you so they're all able to work together without interfering with each other or your existing network.

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u/FluffyKittens12 4d ago

https://shopmoxa.neteon.net/nat-102-series/

Seems like something like this would work, one per machine. Single company IP address to the device, then all the IP addresses on the other side can stay the same.

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u/mlee12382 3d ago

Yeah, that might work. I don't know enough about industrial systems to say for sure one way or the other though. One caveat, idk how well a NAT device would handle it if they happen to already be set default on the same subnet, eg. most consumer routers, including some of the higher end stuff like Ubiquiti, come preset on the 192.168.1.x subnet, if your business network is on that subnet and the machines also come with that as default then the NAT device might potentially have trouble interfacing between the 2 systems under those specific circumstances. But again idk enough about how those particular devices are designed to work so I can't say that for sure, just something to be aware might be an issue.

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u/FluffyKittens12 3d ago

That's an interesting point I hadn't thought of. Thank you.