Show HN: Implementing ping from the Ethernet layer (ARP,IPv4,ICMP in user space)

Show HN (score: 7)
Found: February 23, 2026
ID: 3401

Description

Other
Show HN: Implementing ping from the Ethernet layer (ARP,IPv4,ICMP in user space) I built a user-space implementation of ping that constructs Ethernet frames, performs ARP resolution, builds IPv4 headers, and sends ICMP echo requests manually using AF_PACKET.

- ARP (packet format, cache with aging, re-ARP, conflict handling) - IPv4 header construction and checksum - DF handling and ICMP Fragmentation Needed (Type 3 Code 4) - IP fragment reassembly - ICMP echo request/reply parsing - A basic ping loop with loss statistics

The goal was to understand how packets actually move from Layer 2 upward.

More from Show

No other tools from this source yet.