Can ports reveal IP information?

[scottmohr]

Hello All-

Does anyone know how to find out what IP addresses are sending/receiving traffic through a given port on a 2924XL switch?

In other words, we would like to get information from the switch on which computer each port is servicing. If we know to which IP addresses traffic is directed across a port then it’ll be easy to determine the geographic location that port is connected to. That way we won’t have to trace each wire manually to find out where they go to. MAC addresses would help too, though not as useful as IP. If you have any tricks up you sleeve to automate this process it would be most helpful.

Thanks,

Scott Mohr

Chowchilla Elementary School District

[t.baranski]

The "show mac-address-table" command will provide MAC address -> port associations. If you ping an IP address and then do a "show arp", you can correlate a given IP's MAC address in the ARP table with the MAC address table from the first command.

[pmshah]

I would suggest that you go out and buy Kiwi CatTools (http://www.kiwisyslog.com/) and implement that. It does not even cost $100 but does so much for so little.

CatTools would need access to the router and the switches. It will automatically collect the mac-address and arp tables and will link them up on a scheduled basis.

Regards,

Pritish

[james.amann]

If you have Campus Manager, you can use the User Tracking app to get much of the info you want. It supplies:

User

MAC

IP

HostName

Switch

Port

Speed

Duplex

etc.

You will get the client's MAC address, ie the device directly connected to the switch port, but not the ip's it is talking to. For that you need to look at RMON and or Netflow stats.

Solar Winds has an app that is supposed to retrieve alot of this info, but in practice you mileage may vary (mmv).

James Amann

Georgia State University

[medic · Accepted solution]

User Tracking in Campus Manager usually does the trick for us. Depending on your discovery settings, it will provide end device ip addresses on each switchport. Solar Winds is another tool we use and it's Switch Port Mapper program works really well to map MAC address to IP address to switchport. Hope this helps.

Danny

[scottmohr]

Thanks Everyone-

We will probably go with the SolarWinds product. Did find a very cool inexpensive utility called IP Console that does some of what we're looking for. The Campus Manager product is part of CiscoWorks which has an obscene $19,000 price tag. A bit too much to spend in an economaically depressed area like ours.

Thanks for all your help.

Scott Mohr