Ports and Networks

nmap and net-tools contain a collection of tools and functionality to let you explore your network.

Network Scan

1. ifconfig will tell you your IP address and your subnet.
2. sudo nmap -sn [CIDR] will tell you the other devices on your network, their IP address, and other details when available.
   • -sn : "Ping Scan - disable port scan". This speeds up the request by disabling per-discovered-device port scanning, which can take a while.
   • CIDR : Classless Inter-Domain Routing. See Wiki. It specifies a range of network ports to scan over.
   • An example: sudo nmap -sn 192.168.107.0/24, will scan 192.168.107.0-255.
3. For a scan with additional information per discovered device, run sudo nmap -A -T4 CIDR
   • -A : "Enable OS detection, version detection, script scanning, and traceroute"
   • -T : "Set timing template (higher is faster)"

Port Scan

• nmap [IP Address]
  • nmap port scanning tutorial
  • It will, among othe things, scan the 1000 most popular ports and report back whether or not they are open, and which services are available/listening on those ports.
  • nmap -p 80[,443,...] example.com will scan a specific port

Common Ports and Services

• :22/tcp - ssh. Allows remote connection.
• :23/tcp - telnet. It's its own thing :D.
• :53/tcp - domain. DNS server. Routers will commonly open this port.
• :80/tcp - http. Any web browser can display comms.
• :554/tcp - rtsp. Real Time Streaming Protocol. E.g., used by IP cameras for streaming videos. VLC video player can display RTSP streams.
• :9010/tcp - sdr. Software Defined Radio? I see it on IP video cameras.