How to find the IP addresses of devices attached to ports of SG-300-52

[paulchalupsky]

I have recently purchased an SG-300-52 Managed Switch. (This is the first managed switch I have used, so I am trying to figure out what I can do with it and how it works.)

I would like to know how to find out the IP address of each computer connected to each port of the switch. Is this possible and if so how can I do this from the browser interface? If  you could explain it as if you were talking to a 5-year old, hopefully I will be able to understand. Thanks, Paul

[w_smith]

I don't think you can, it doesn't really work that way, the switch works at ISO layer 2 (MAC addresses) while IPV4 is ISO layer 3.

You _might_ be able to find the MAC address of the device on the other end, and get your DHCP server to tell you what IP address goes with that MAC address, but that's non-trivial.

There is some SNMP stuff on my SG500 at:

IP-MIB::ipNetToMediaPhysAddress.300000.192.168.1.50 = STRING: 40:6c:8f:20:1f:38

but there doesn't seem to be anything that tells me what port it's on, and there are only 3 entries there, so probably just things I have IP connections open to or something.

You _might_ get somewhere by putting it into Layer 3 mode, but that's out of my experience.

[Tom Watts]

w_smith is pretty on key, the best you can do at the present time is look at the switch mac address table then match your MAC addresses against your DHCP server entries or router tables.

+5 for the snmp, I'm glad you're putting the mibs to work

-Tom
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[paulchalupsky]

Thanks for the responses! I would be fine with being able to get all of the Mac addresses and which port they're on. However when I look at the "Mac Address Tables"--"Dynamic Addresses" in the web menu, there are only 6 Mac addresses showing, whereas I have 30 computers online. How do I get them all to show up here?

[w_smith]

Umm, maybe ping them all to get the tables to populate?  The tables probably age out in case you move a device from one port to another.

[paulchalupsky]

How do I ping them ?

[Tom Watts]

On a windows computer, start menu -> all programs -> accessories -> command prompt

ping ip address -> ping 192.168.1.10

If you have a firewall on the computer you're trying to ping it will block the ping message, may need to disable some firewalls or allow exceptions for this.

-Tom
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[paulchalupsky]

I've pinged the ip addresses of the attached computers, but I'm still not getting more than the orginal 6 mac addresses to show up in the Table. Any ideas on how to get all of them to show up in the Mac Address table?

[w_smith]

I'm seeing lots of MAC addresses in my tables, but I've got continuous traffic.

Did you look at the MAC tables within 5 minutes of pinging all the IP addresses?  Dynamic Address settings is (default) 300 seconds, if yours is shorter or it took you a while to ping them all, then maybe they are timing out?

If you have a box that'll run nmap, that'll ping everything for you pretty quickly.

[Tom Watts]

The mac address table should populate basically everything that has passed through the switch and any directly connected devices.

-Tom
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