Identifying the IP of devices on certain ports

[just_david]

We're trying to update our inventory of switches and thier IP's.

 

I was wondering if theres a way to do this from our core switch.

Literately scan port by port for whats at the other end.

 

I'm hoping for something along the lines of, on port b1 is device X on IP X (but just the IP would be enough)

 

Is that dooable? an sh arp command?

[SpaceInvader83]

You can obtain the MAC address using sh cdp neighbour would help depending on the device (If it supports CDP) or sh mac address could be helpful. Then in turn look at DHCP or ARP table. Edited July 5, 2016 by SpaceInvader83

[markwilfan]

Spiceworks will do this for you.

[Mr.Ben]

You can use Link Layer Discovery Protocol.

 

LLDP should be already enabled on your core switch. You can then run:

 

sh lldp info remote-device

 

From the console. This will give you a list of devices (that support lldp, normally other switches and access points) and ports that on which they are attached.

 

You can then run (where XX is the port number)

 

sh lldp info remote-device XX

 

Which will give you detailed information, including the IP.

 

From this, you can find the IP of other switches, connect to them with putty and repeat:-)

Edited July 7, 2016 by Mr.Ben

[just_david]

thanks folks I'll give all of those a try

[Mr.Ben]

Hi David,

 

As you are running HP, CDP won't be supported (Cisco Discovery Protocol).

 

Ben

[just_david]

Worked like a charm ben thanks

[IanT]

Hi David,

 

As you are running HP, CDP won't be supported (Cisco Discovery Protocol).

 

Ben

 

CDP will work on HP - I use this all the time!

 

On lower\entry level HP switches I believe CDP is not available

[just_david]

CDP will work on HP - I use this all the time!

 

On lower\entry level HP switches I believe CDP is not available

 

We've got some pretty budget hp switches in to replace some old netgears. I'll try both methods and let you both know the results ^^

[IanT]

We've got some pretty budget hp switches in to replace some old netgears. I'll try both methods and let you both know the results ^^

 

cool - which models?

[just_david]

some 1820's that went in this year in place of some failing netgears.

 

they are all at the far ends of the network. any heavy lifting is done on 2500 and 2900 series I think.

 

mr ben probably knows more than i do at the moment ^^ it's a fun learning curve that i've put off for far too long

[just_david]

well we have a far healthier, if still far from perfect network map now.

 

no dice on the 1820's. they show up but aren't able to run it, but lldp and cdp worked on all the procurves

 

need to fill in the gaps the netgears leave now

[Mr.Ben]

Good stuff :-) It was something that would have got done with the knowledge that I have now :-)