Port Scanner

Scan TCP open ports on a server.

Getting Started

cc -o scan tcp_scan.c
scan IPV4_ADDRESS

Usage

$ ./scan -h
Usage: [-SC] <ip address>
-S default, scan with SYN packets
-C scan with connect(), i.e. the whole 3-way handshake procedure

NOTE

1. Scanning with SYN packets (the default mode) only works on linux, since *BSD systems are not allowing applications to read packets through raw sockets for security issues.
2. When you want to scan ports with SYN packets (on linux, of course), sudo priviledge may be required. Or, you can use the linux capbilities with sudo setcap cap_net_admin,cap_net_raw=eip scan, and then run it as normal.

References

• A brief programming tutorial in C for raw sockets
• SYN flooder
• Using Linux Raw Sockets
• Linux IPv4 raw sockets