Here's a link back to my main GitHub page.

These are basic techniques for C network programs on Linux.

• A TCP client and server in C
• A UDP client and server in C
• A DNS lookup in C
• UNIX domain sockets in C
• List network interfaces in C
• libpcap examples in C

Also cidr-tool is a command-line CIDR calculator. It can expand a CIDR, make CIDR ranges from an IP range, etc.