networking-labs-cli

Python network automation CLI for DNS lookup, port checks, connectivity testing, AWS VPC/EC2 concepts, and CI/CD validation.

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Purpose

This project demonstrates practical network engineering skills through a working command-line tool. Every command maps directly to a real troubleshooting workflow used in NOC, cloud support, and infrastructure roles.

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Target Roles

• Network Support Engineer
• Cloud Support Engineer
• NOC Analyst
• Infrastructure Support / L1/L2 Operations

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Skills Demonstrated

Skill	Where
DNS lookup (A, AAAA, PTR records)	nmcli/core.py → dns_lookup()
TCP port scanning (open/closed audit)	nmcli/core.py → port_scan()
ICMP connectivity testing	nmcli/core.py → ping()
Route path analysis	nmcli/core.py → traceroute()
AWS VPC enumeration via boto3	nmcli/aws.py → get_vpc_info()
AWS EC2 instance inventory	nmcli/aws.py → get_ec2_instances()
Python CLI with argparse	main.py
Unit testing with pytest	tests/test_core.py — 5/5 passing
CI/CD pipeline validation	.github/workflows/test.yml
Input validation and error handling	nmcli/utils.py → validate_host()

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Tech Stack

Layer	Technology
Language	Python 3.10+
AWS SDK	boto3 / botocore
CLI Framework	argparse
Testing	pytest
CI/CD	GitHub Actions (ubuntu-latest)
Packaging	setuptools + pip

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Project Structure

networking-labs-cli/
├── main.py                        # CLI entry point — 6 subcommands
├── nmcli/
│   ├── core.py                    # ping, traceroute, dns_lookup, port_scan
│   ├── aws.py                     # get_vpc_info, get_ec2_instances (boto3)
│   └── utils.py                   # validate_host, logging config
├── tests/
│   └── test_core.py               # 5 unit tests — all passing
├── labs/
│   ├── 01-dns-troubleshooting.md  # DNS triage runbook
│   └── 02-network-connectivity.md # Full connectivity lab walkthrough
├── docs/
│   └── network-support-runbook.md # NOC-style escalation runbook
├── sample-output/
│   └── network-check-output.txt   # Real CLI output examples
├── scripts/
│   └── net-diag.sh                # Shell diagnostic helper
├── .github/workflows/
│   └── test.yml                   # CI pipeline — runs pytest on every push
├── requirements.txt
└── setup.py

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How to Run

# Set up environment
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
pip install -e .

# Run the CLI
nmcli dns google.com
nmcli ping 8.8.8.8 --count 4
nmcli portscan github.com --ports 22 80 443
nmcli traceroute cloudflare.com

# AWS commands (requires: aws configure)
nmcli aws-vpc
nmcli aws-ec2

# Run tests
python3 -m pytest tests/ -v

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Sample Output

DNS Lookup

$ nmcli dns github.com
  A        → 140.82.114.4
  AAAA     → (not available)
  PTR      → lb-140-82-114-4-sea.github.com

Port Scan

$ nmcli portscan github.com --ports 22 80 443
PORT     SERVICE          STATUS
-----------------------------------
22       SSH              OPEN
80       HTTP             OPEN
443      HTTPS            OPEN

Summary: 3 open, 0 closed

Ping / Connectivity

$ nmcli ping 8.8.8.8 --count 4
PING 8.8.8.8: 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=118 time=11.2 ms
64 bytes from 8.8.8.8: icmp_seq=1 ttl=118 time=10.8 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=118 time=11.5 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=118 time=10.9 ms

--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss

AWS VPC

$ nmcli aws-vpc
VPC ID                 CIDR                 DEFAULT    STATE
-----------------------------------------------------------------
vpc-0abc1234def56789   10.0.0.0/16          False      available
vpc-0default000000000  172.31.0.0/16        True       available

See sample-output/network-check-output.txt for the full run.

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CI/CD Pipeline

Run	Trigger	Result
#1	Initial workflow push	Failed — misconfigured Actions version
#2	Actions version fix	Failed — missing setuptools import
#3	Autonomous CI repair branch	Passed
#4	Merge to main	Passed

Root cause of initial failures: outdated Actions versions + missing setuptools in setup.py. Diagnosed and resolved via Claude Code autonomous repair mode.

Current status: all pushes to main trigger automated pytest — 5/5 tests pass.

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What This Project Proves

• Can write a modular Python CLI from scratch using argparse and socket libraries
• Understands DNS record types (A, AAAA, PTR) and how to query them programmatically
• Knows TCP connectivity state — port scan logic uses connect_ex() to detect open/closed ports
• Familiar with AWS SDK (boto3): can enumerate VPCs, describe EC2 instances, handle NoCredentialsError
• Can write and maintain pytest test suites, including mocking AWS SDK calls
• Can read, debug, and fix broken GitHub Actions CI pipelines
• Applies structured logging and input validation to CLI tools

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Next Improvements

• Add --region flag to AWS commands
• Add SNMP polling module
• Add JSON/CSV output format option
• Add route table and security group inspection
• Integrate with AWS CloudWatch for metric queries

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Recruiter Note

Every command in this tool maps to a task performed daily in network support and cloud operations roles: checking if a DNS record resolved correctly after a change, auditing which ports are exposed on a server, verifying ICMP reachability, and inventorying AWS infrastructure. The CI pipeline ensures nothing is broken before it ships. The test suite validates behavior without requiring a live network or AWS account.

AWS Cloud Practitioner in progress.

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Author: Carter | github.com/CartierC