How can I find private IP address of a device?

Question

I 'm trying to detect IP address of a Wireless Access Point device, connected via Ethernet on my router. Router's configuration page shows status of the Ethernet port is up, but no device connected.

If I 'm correct, any device attached on the router, requests for a private IP address (at least this happens when I attach another device). However, seems that no IP has been assigned on this device. Is this possile?

nmap result:

Starting Nmap 6.00 ( http://nmap.org ) at 2014-03-09 18:30 EET
Nmap scan report for 192.168.1.1
Host is up (0.058s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
23/tcp   open  telnet
8080/tcp open  http-proxy

Nmap scan report for 192.168.1.103
Host is up (0.00019s latency).
All 1000 scanned ports on 192.168.1.103 are closed

Nmap scan report for 192.168.1.111
Host is up (0.00083s latency).
Not shown: 991 closed ports
PORT     STATE SERVICE
135/tcp  open  msrpc
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
1025/tcp open  NFS-or-IIS
1026/tcp open  LSA-or-nterm
1027/tcp open  IIS
1028/tcp open  unknown
1029/tcp open  ms-lsa
1030/tcp open  iad1

Nmap scan report for 192.168.2.68
Host is up (0.045s latency).
Not shown: 999 closed ports
PORT   STATE    SERVICE
25/tcp filtered smtp

Nmap done: 65536 IP addresses (4 hosts up) scanned in 172.36 seconds

Hosts detected:

1. 192.168.1.1 -> Router
2. 192.168.1.103 -> VirtualBox
3. 192.168.1.111 -> PC
4. 192.168.2.68 -> unknown

How can I ensure if an IP has already been assigned and how can I find it's IP?

Answer 1

1. Connect AP directly to PC
2. Start tcpdump -ni eth0 on PC
3. Reboot AP
4. Look carefully to tcpdump output. AP should announce his IP, or try to request it via DHCP.

Answer 2

Try logging into your router and see what ip address it has assigned. I am correct to think that your subnet mask is 255.255.255.0 on your hosts? You can also scan all active ip address using an app called angry ip. http://angryip.org/w/Download