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I tried to scan my network for hosts. However, it seems like it didn't scan the MAC. I tried all kinds of TCP and UDP scans on different kind of ports but the hosts doesn't show up.

It's strange because I can ping to the host and it's on the same network, so don't really get why it doesn't show up in the list.

I already tried this: How to find live hosts on my network? but didn't worked for me.

Community
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John
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3 Answers3

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If you can ping it, nmap should show it in the output if you perform a ping scan. Are you sure to use the right parameters?

  • A ping scan did the work... I looked that over. Can you maybe clarify why a UDP/TCP or a regular scan didn't work? – John Mar 07 '16 at 20:49
  • I'm not sure but I think that the firewall is blocking certain types of scans. –  Mar 07 '16 at 20:57
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From nmap online manual

If no host discovery options are given, Nmap sends an ICMP echo request, a TCP SYN packet to port 443, a TCP ACK packet to port 80, and an ICMP timestamp request. (For IPv6, the ICMP timestamp request is omitted because it is not part of ICMPv6.) These defaults are equivalent to the -PE -PS443 -PA80 -PP options. The exceptions to this are the ARP (for IPv4) and Neighbor Discovery (for IPv6) scans which are used for any targets on a local ethernet network. For unprivileged Unix shell users, the default probes are a SYN packet to ports 80 and 443 using the connect system call. This host discovery is often sufficient when scanning local networks, but a more comprehensive set of discovery probes is recommended for security auditing

give it a try with something like nmap -F yourNetworkAddress/YourNetMask (if you dont know how to calculate the submask search for network calculator like this). If you are starting to use nmap the visual GUI (zenmap) , reading the manual and analyze the network traffic you are generating (use wireshark)will really help you to understand what you are doing in the under layer , and will prevent you to do anything dangerous for you and other users.

Sarastro
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I had the same issue. Nmap showed only the router and my own computer when scanning the whole network quickly with nmap -F [ip/sub]. To allow a full scan you have to provide root rights on MacOS. Make sure you have sudo nmap -F [ip/sub] to detect all devices.

XKeyScore
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    Had the same issue. It cannot discover some IPs if it's run without root privileges. With root privileges, it can discover all the hosts. – Kasun Aug 15 '19 at 05:12