I've recently inherited a building that has a network set up without any documentation. There are no labels on the cables, and many of them have been spray painted over, making it difficult to determine where each switch port leads. For instance, I have no idea what devices are connected to switch port 16 or 17—whether they go to desks, offices, or conference rooms. I've never dealt with this kind of situation before, so I'm looking for advice on effective methods to trace these connections. Would using a multimeter or some cable testing device be the best approach? I want to avoid accidentally disconnecting any important devices, especially those relying on Power over Ethernet (PoE). Any tips or experiences would be greatly appreciated!
5 Answers
If your switch isn't smart, you'll need to test each cable with a good cable tester. There are some inexpensive options like Netool that can help you figure out where each cable goes. If you do have a managed switch, export the MAC address table to get a clearer idea of what's connected.
Yeah, definitely consider investing in a cable tester. They can track multiple cables, and having one really speeds up the process. Good luck with the mapping!
What type of switch do you have? If it's capable of CDP or LLDP, you can quickly document the live ports just by using a laptop. If it's a dumb switch, you might have to tone out the cables manually, but it's worth getting a decent toner to help with that process.
I suggest using a CDP or LLDP tool on your laptop to connect to each port. These protocols will help you identify what devices are connected. If nothing shows up, use a cable toning tool to track down the right patch for any offline ports. Back in the day, I even wrote a program to pull MAC tables from the switch, which helped a lot in mapping everything out!
I’d advise against doing it all at once unless it’s absolutely necessary. Mapping things over time can often be more practical. For client-side connections, unless there’s a pressing need, you might find it easier to document as you go. It’s less overwhelming that way!
If your switch supports LLDP, you can really streamline this process. Just plug your laptop in and let it listen for traffic. You might need a program to get all the info, but once you get the hang of it, it saves so much time. If you're doing it solo, just keep looking at the logs as you test each port.
LLDP is like magic! Just be sure to have the right software installed. Many Linux distributions come with it available, making it easy to get valuable data.
For sure, LLDP will help a ton. It’s definitely worth utilizing if you have the right setup!
Netool is excellent! When I plug in, it tells me which port and switch I'm connected to and even shows the switch name. I also recommend getting a cable finder or tester that can check multiple cables at once; it makes life so much easier. Plus, you’ll want a label maker to keep everything organized once you map it out!