icmp-timecheck 1.1.3

Convert ICMP Timestamp replies into human‑readable times and report clock offsets.

icmp-timestamp

A small toolkit to convert ICMP Timestamp (type 13/14) replies into human‑readable times and to report clock offsets.

This repository contains:

• timecheck.py — a Python/Scapy-based tool that queries ICMP Timestamp and reports NTP-style offsets.
• icmp-timestamp.sh — a Bash helper that converts numeric millisecond timestamps to human-readable UTC datetimes.
• pry_bar.sh — a small driver that uses hping3 to probe hosts, parses RTT/timestamp values, and calls icmp-timestamp.sh.

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Prerequisites

• Python 3.8+ and pip (for timecheck.py).
• scapy Python package (install via requirements.txt or directly).
• hping3 for the Bash flow (pry_bar.sh and direct hping3 use).
• Elevated privileges (root / sudo) are typically required to send/receive raw ICMP packets.

Install system packages (examples):

Debian / Ubuntu (For bash script using hping3)

sudo apt update
sudo apt install -y hping3

macOS (Homebrew)

brew install hping

Python (For Python script using scapy)

python3 -m pip install -r requirements.txt

With Pip

pip install icmp-timestamp

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Using the Python tool (timecheck.py)

timecheck.py uses Scapy (AF_PACKET) to send ICMP Timestamp requests. It usually requires sudo.

Examples:

Query hosts from a file (one host per line)

sudo python3 timecheck.py hosts.txt

With a 3 second timeout and verbose per-host timing

sudo python3 timecheck.py hosts.txt --timeout 3 --verbose

Write results to CSV

sudo python3 timecheck.py hosts.txt --csv results.csv

timecheck.py prints a compact table of remote times, offsets vs local clock, RTTs, and a simple assessment.

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Using the Bash flow (hping3 + pry_bar.sh + icmp-timestamp.sh)

icmp-timestamp.sh can be used standalone to convert numeric millisecond timestamps into human-readable times. For example:

pry_bar.sh drives hping3, extracts round-trip min/avg/max values, and calls icmp-timestamp.sh which converts numeric millisecond timestamps into human-readable times.

Notes:

• hping3 requires root privileges — run with sudo.
• pry_bar.sh parses hping3 output for round-trip min/avg/max. It prints per-target RTTs and forwards them to icmp-timestamp.sh.
• icmp-timestamp.sh expects numeric millisecond timestamps (or values parsed by pry_bar.sh) via -O (Originate), -R (Receive), -T (Transmit). Example:

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