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Is there any way that you can find all the IP addresses within a LAN without assigning a IP address to you NIC?

I know most of the tools like angryipscanner, arp-scan, nmap and others can mostly identify the hosts within a particular IP range and with your NIC assigned with an IP address.

What if I wanted to find all the addresses within a LAN just by plugging my NIC to a switch and using for example ARP for all the nodes connected to the network to reply an arp request with their IP address and MAC address using only my NICs MAC address.

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No, that's not possible. You cannot use the TCP/IP tools without an IP address. That would be like connecting to a network without a network card.

What would be possible is test MAC address to MAC address communication, but both NICs would have to have similar firmware loaded and knowledge of each other's MAC address to be able to do this (Intel cards used to be able to do this 20 years ago).

Sorry to be the harbinger of bad news...

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  • Is it possible to somehow modify the ARP methodology on frame level and send an broadcast arp-request frame to all the nodes connected to one LAN (without assigning an IP address to your NIC) and make all the nodes send an arp reply to the MAC address where your NIC is connected to. Using libpcap for example? Thanks for the answer tho. – mario May 31 '15 at 18:32
  • Nope: to receive the answers back you need to give your IP address in the arp-request... Have a look here instead why it isn't possible... And as you're a reputation 6 user: If this answer helped you, don't forget to click the grey at the left of this text, which means "yes, this answer is valid"! ;-) – Fabby May 31 '15 at 18:42
  • So probably the closest way to get to know all the hosts IP addresses connected to you LAN (taking under consideration that they could be on different IP subnets) is by inspecting the routers ARP Cache ? I'm still wondering why it isn't possible. I'll try to find it in the book you've linked me. – mario May 31 '15 at 18:47
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    Unless its a ubuntu server running as a router :) – mario May 31 '15 at 19:28
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    @mario that's typically handled by the router via DHCP (although I know several corporate environments where everything is static IP and not DHCP-assigned). If you do not know what IPs exist in a network and need to set the IP for your system and there is no DHCP, you're pretty much stuck without a solution. Static IP assignment is usually used to prevent the "jack in and see IP and network data" problem (along with other defenses and equipment) – Thomas Ward Jun 1 '15 at 9:42

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