Many development teams make the same mistake - treating system administration as an afterthought. We recently learned this lesson the hard way when our improperly configured infrastructure caused:

• EMI interference from subpar CAT6 cabling (dB loss measured at 22.3 vs spec 19.8)
• WPA2 Enterprise implementation with vulnerable RADIUS configuration
• Server hardware recommendations that didn't account for our CI/CD pipeline requirements

Instead of generic questions, try these scenario-based assessments:

# Sample troubleshooting scenario
$ sudo tcpdump -i eth0 -nn -c 100 'port 53' | grep "NXDOMAIN"
# Ask candidate to interpret DNS query failures shown in this capture

Network Design Test: Present our office floor plan (2500 sq ft, 35 devs) and ask for:

• Switch placement plan with justification
• VLAN segmentation strategy for dev/staging/prod
• Wireless channel allocation for 5GHz spectrum

Request demonstration of:

# Ansible playbook for web server hardening
- name: Harden Nginx
  hosts: webservers
  become: yes
  tasks:
    - name: Disable server_tokens
      lineinfile:
        path: /etc/nginx/nginx.conf
        regexp: '^server_tokens'
        line: 'server_tokens off'

Cable Management Audit: Ask for photos of previous cable plant implementations with explanations of:

• Bend radius maintenance
• Patch panel labeling system
• Testing methodology (Fluke reports)

Watch for these warning signs:

1. Cannot explain difference between TCP BBR and CUBIC congestion control
2. Unfamiliar with OAuth2 flow for internal tool authentication
3. No experience with infrastructure-as-code tools (Terraform/Pulumi)

Competent candidates should articulate solutions for:

# Example GitLab CI/CD pipeline requirements
stages:
  - test
  - build
  - deploy

variables:
  POSTGRES_PASSWORD: $CI_DB_PASSWORD

services:
  - postgres:13.2-alpine

They should explain how they'd optimize this for:

• Security (image scanning, secret management)
• Performance (caching strategies)
• Reliability (retry logic, monitoring)

As developers, we often assume technical competency transfers across domains - this is particularly dangerous when hiring system administrators. The core disconnect stems from different evaluation criteria:

// Bad evaluation pattern we followed initially
if (candidate.hasCertification("CCNA") || 
    candidate.mentionedKeywords("cloud", "security")) {
    hireCandidate(); // This fails in practice
}

Create practical tests that mirror real-world scenarios:

• Network Design Challenge: Provide office blueprints and ask to design cable runs with Cat6/6a specifications
• Security Audit Simulation: Give sample firewall rules and ask to identify vulnerabilities

# Sample test question for WiFi security
"""
Given this wpa_supplicant configuration, identify 3 security issues:

network={
    ssid="CorpWiFi"
    psk="company123"
    key_mgmt=WPA-PSK
    proto=WPA
    pairwise=TKIP
    group=TKIP
}
"""
# Expected answers: 
# 1. Weak PSK (should be 12+ chars with complexity)
# 2. Using TKIP (should be CCMP)
# 3. No 802.1X authentication

Present candidates with your current stack and growth projections, then evaluate their:

1. Hardware specification rationale (RAM/CPU/storage calculations)
2. Monitoring solution architecture (Prometheus vs Nagios etc.)
3. Disaster recovery planning (RPO/RTO understanding)

Beyond technical skills, watch for these patterns during interviews:

Ask for opinions on proven patterns:

"""
How would you structure backups for:
- 50GB PostgreSQL DB with 100+ transactions/sec
- 5TB of build artifacts in S3
- Containerized microservices with dynamic scaling
"""

Look for answers that address retention policies, incremental vs full backups, and testing procedures.