How can I find the IP address of a host plugged into an Arista switch?

You can find the IP address through a combination of the switch's internal MAC address table, and nmap from another host on the network

SSH into the Arista switch and run show mac address-table

You will get an output like:

 

arista0>show mac address-table

         Mac Address Table

------------------------------------------------------------------

 

Vlan    Mac Address       Type        Ports      Moves   Last Move

----    -----------       ----        -----      -----   ---------

   1    0000.c9db.5490    DYNAMIC     Et49       1       2 days, 4:25:58 ago

   1    0000.c9db.5494    DYNAMIC     Et49       1       1 day, 8:33:47 ago

   1    000b.ab77.d925    DYNAMIC     Et38       1       5:10:20 ago

   1    000d.b932.a328    DYNAMIC     Et1        1       99 days, 5:22:13 ago
   1    00c0.ff19.807d    DYNAMIC     Et39       1       35 days, 23:53:23 ago

 

 

Let's say that you know the device you're trying to get into is on on port 39, then the last line is the one we're concerned with. We can use the last two octets of (80:7D) 

Now, from a Mac client that has nmap installed, we will search for those MAC octets:

mrj@mrj-mbp:~$ sudo nmap -sP 10.0.0.0/24 | grep -B 2 -i 80:7d

Password:

Nmap scan report for 10.0.0.149

Host is up (0.012s latency).

MAC Address: 00:C0:FF:19:80:7D (DOT Hill Systems)


 

There we go. The IP address is 10.0.0.149

Matthew Jensen
2018-10-19 20:46