DEKSI Network Administrator Best Practices: Security, Monitoring & Troubleshooting

Least privilege: Apply role-based access control (RBAC); give users and services only the permissions they need.
Network segmentation: Segment management, production, and guest networks; use VLANs and access control lists (ACLs).
Zero trust principles: Authenticate and authorize every device and user for each request; enforce MFA for administrative access.
Patch management: Maintain an automated patching schedule for firmware, OS, and network device software; test patches in a staging environment before production.
Secure device configurations: Harden device defaults (disable unused services/ports, change default credentials), store configs in a secure configuration management system, and sign/configure images when supported.
Encryption: Use strong encryption (TLS 1.⁄₁.3, IPsec) for management traffic, user data in transit, and VPNs.
Secrets management: Centralize credentials, keys, and certificates in a secrets manager; rotate keys and certificates on a schedule.
Logging & audit trails: Ensure all security-relevant events (logins, config changes, firewall rule edits) are logged and retained according to policy.
Vulnerability scanning & pen testing: Run regular scans and periodic pen tests; track remediation with a ticketing system.
Incident response plan: Maintain and rehearse an IR plan that includes isolation procedures for compromised devices and recovery playbooks.

Centralized monitoring platform: Use an NMS or observability stack (SNMP/NetFlow/sFlow, syslog, telemetry) to collect metrics, logs, and flows centrally.
Baseline and anomaly detection: Establish normal baselines for bandwidth, latency, CPU/memory, and use threshold and anomaly alerts to detect deviations.
Health checks & synthetic testing: Implement active probes (ICMP, HTTP, transaction tests) to validate service health from multiple locations.
Real-time alerting with prioritized rules: Create severity levels (Critical/High/Medium/Low) and route alerts to the right on-call person with escalation policies.
Dashboards for key SLAs: Maintain dashboards for availability, latency, packet loss, and throughput; refresh views for executives and engineers.
Capacity planning: Monitor utilization trends and project capacity needs; set triggers to initiate expansion before saturation.
Telemetry and observability best practices: Prefer streaming telemetry where available; collect structured, time-series data and correlate with logs/traces.
Log retention and indexing: Define retention periods; use indexed logs for fast search and root-cause analysis.
Automated remediation: Where safe, automate common fixes (e.g., service restarts, route flaps mitigation) and document rollbacks.

Structured troubleshooting workflow: Follow a standard process: gather facts, reproduce (if safe), isolate domain (physical/link/network/service), form hypothesis, test, implement fix, verify, and document.
Runbooks and playbooks: Maintain concise runbooks for common incidents (link down, routing loop, high CPU) with exact commands and expected outputs.
Correlation and context: Correlate monitoring alerts with recent config changes, maintenance windows, BGP updates, or software upgrades.
Tooling: Keep a toolbox of packet captures (tcpdump/wireshark), traceroute/mtr, interface statistics, routing tables, and flow records.
Packet-level analysis: Capture at ingress/egress points for intermittent issues; timestamp and correlate with application logs.
Rapid rollback capability: Use version-controlled configs and staged deployments with the ability to rollback quickly.
Post-incident review: Run blameless postmortems with timelines, root cause, corrective actions, and owners; track action completion.
Knowledge base: Keep a searchable KB of incidents, symptoms, causes, and fixes to speed future troubleshooting.

Configuration management & IaC: Manage device configs with tools (Ansible, Salt, Git) and treat them as code with reviews and CI checks.
Change management: Enforce scheduled changes, approval workflows, and pre/post-change validation; maintain a change calendar.
Backups & recovery: Regularly back up configs and state; test restores periodically.
Automation & scripting: Automate repetitive tasks (inventory, compliance checks, certificate renewals) and validate automated actions in staging.
Documentation: Maintain up-to-date network diagrams, IP addressing plans, and contact rosters.
Vendor lifecycle management: Track hardware/firmware EOL/EOS and plan refreshes to avoid unsupported equipment.

Daily: Check critical alerts, device reachability, backup status.
Weekly: Review logs for anomalies, verify backups, check certificate expirations.
Monthly: Patch schedule progress, capacity trends, run tabletop IR exercises.
Quarterly: Pen test review, disaster recovery test, vendor EOL assessment.

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