name: networking-skill description: Network protocols and troubleshooting - TCP/IP, DNS, HTTP/HTTPS, SSH, firewalls. sasmp_version: "1.3.0" bonded_agent: 02-networking-protocols bond_type: PRIMARY_BOND

parameters:

• name: protocol type: string required: false enum: ["tcp", "udp", "http", "https", "dns", "ssh", "all"] default: "all"
• name: operation type: string required: true enum: ["diagnose", "configure", "secure", "monitor"]

retry_config: strategy: exponential_backoff initial_delay_ms: 1000 max_retries: 3

observability: logging: structured metrics: enabled

Networking Skill

Overview

Master networking fundamentals for DevOps infrastructure management.

Parameters

Core Topics

MANDATORY

• TCP/IP and OSI model
• DNS configuration and troubleshooting
• HTTP/HTTPS and TLS
• SSH key management and tunneling
• Firewall basics (iptables, ufw)

OPTIONAL

• Load balancing
• VPN and tunneling
• Traffic analysis with tcpdump

ADVANCED

• BGP and routing protocols
• SDN concepts
• Zero-trust networking

Quick Reference

# DNS
dig +trace example.com
dig @8.8.8.8 example.com
host -t MX example.com

# TCP/IP Diagnostics
ping -c 4 host
traceroute host
ss -tuln
ip addr show

# HTTP Testing
curl -I https://example.com
curl -v https://example.com

# SSL/TLS
openssl s_client -connect host:443
openssl x509 -in cert.pem -text -noout

# SSH
ssh-keygen -t ed25519
ssh-copy-id user@host
ssh -L 8080:localhost:80 user@host
ssh -D 1080 user@host

# Firewall (UFW)
ufw status verbose
ufw allow 22/tcp
ufw deny from 192.168.1.100

# Firewall (iptables)
iptables -L -n -v
iptables -A INPUT -p tcp --dport 22 -j ACCEPT

Troubleshooting

Common Failures

Debug Checklist

1. Layer 1-2: Link up? ip link show
2. Layer 3: Ping gateway?
3. Layer 4: Port open? ss -tuln
4. DNS: Resolving? dig hostname
5. Firewall: Allowing? iptables -L

Recovery Procedures

Lost SSH Access

1. Use cloud console/IPMI
2. Check sshd: sshd -t
3. Verify firewall: iptables -L -n

Resources

• TCP/IP Guide
• Mozilla SSL Config