ICS/SCADA › Module 6 › Lesson 2
Firewall OT
OT firewall literacy names allowlists, stateful inspection limits, and rule documentation habits on YOUR $OT_LAB — defensive OT literacy only; no real-plant attacks, unauthorized OT scans, or exploit cookbooks.
Visual · t38_firewall_ot
Firewall OT literacy. $OT_LAB only. Original Cyberlium.
Opening
OT firewalls need allowlists and documented rules — literacy teaches review habits, not bypass tricks on live gear.
OT firewall rules should default deny, allow only required ports/protocols between zones, document business justification, and schedule periodic reviews. Practice rule documentation rows on fictional conduits — never publish bypass techniques for employer OT appliances. Cyberlium Topic 38 practices on $OT_LAB — YOUR fictional OT templates, zone diagrams, and labeled checklists under $HOME/cyberlium-lab/t38-ot/ no real-plant attacks, unauthorized OT scans, or exploit cookbooks. Next: Remote Access Hygiene.
1. What Firewall OT covers (named)
Firewall literacy: allowlist vs IT ACL sprawl, rule naming, owner, review date, logging enabled. OT-specific: avoid deep inspection breaking latency-sensitive protocols without testing. On $OT_LAB, document literacy rows on fictional LAB-OT-001 — never live plant IPs, credentials, or exploit steps.
Write firewall rule documentation row — zone pair, ports, justification, review date. Fictional conduit from M6-1 diagram. On $OT_LAB, document literacy rows on fictional LAB-OT-001 — never live plant IPs, credentials, or exploit steps.
Command guide
Try these commands — What Firewall OT covers (named)
═══ TOOLS & WEBSITES ═══ Browse / read these (authorized learning only — stay in YOUR lab / program scope)
NIST SP 800-82 — https://csrc.nist.gov/publications/detail/sp/800-82/rev-3/final CISA ICS — https://www.cisa.gov/topics/industrial-control-systems
═══ INSTALL ═══
Linux (Debian/Ubuntu):
Command — copy this
sudo apt install python3
macOS:
Command — copy this
brew install python3
Windows: Download https://python.org/downloads/
═══ LINUX / macOS ═══
Command — copy this
export OT_LAB=${OT_LAB:-$HOME/cyberlium-lab/t38-ot}
cat > "$OT_ZONES/firewall-rules-stub.csv" <<'EOF'
rule_id,src_zone,dst_zone,ports,protocol,justification,review_date
FW-001,Enterprise,DMZ,443,TCP,jump host access,2026-09-01
FW-002,DMZ,OT,502,Modbus TCP,SCADA to PLC (fictional allowlist),2026-09-01
EOFCommand — copy this
grep -E 'FW-00[12]|justification' "$OT_ZONES/firewall-rules-stub.csv"
Primary tools to practice this lesson: grep, python3. Reference sites: NIST SP 800-82 (https://csrc.nist.gov/publications/detail/sp/800-82/rev-3/final); CISA ICS (https://www.cisa.gov/topics/industrial-control-systems). Run every command in the box — install first, then the usage lines — only on YOUR lab / program scope.
2. Why Firewall OT matters for defenders
Rule documentation survives staff turnover and audits. Temporary 'any-any' rules become permanent breaches. On $OT_LAB, document literacy rows on fictional LAB-OT-001 — never live plant IPs, credentials, or exploit steps.
Students draft rule rows on lab templates. Production changes follow OT change control. On $OT_LAB, document literacy rows on fictional LAB-OT-001 — never live plant IPs, credentials, or exploit steps.
3. $OT_LAB boundary
Forbidden: firewall bypass tutorials on live OT appliances. Allowed: firewall rule documentation literacy row. On $OT_LAB, document literacy rows on fictional LAB-OT-001 — never live plant IPs, credentials, or exploit steps.
Ship: firewall rule row. Next: Remote Access Hygiene.
4. What you ship: firewall ot card for $OT_LAB
OT firewall literacy names allowlists, stateful inspection limits, and rule documentation habits. $OT_LAB named. NEVER real-plant attack steps. chmod 600.
5. What you record before the next lesson
Date (UTC). Firewall OT card. $OT_LAB named. File t38-m06-l02-firewall-ot.txt chmod 600.
6. Wrong vs right: plant attacks vs YOUR OT lab sims
Worked failure — same MSF word, opposite target. Right never needs a café Wi-Fi or classmate laptop.
Wrong
Add temporary any-any rule on live OT firewall without ticket.
Right
Write firewall ot card for YOUR $OT_LAB. Next: Remote Access Hygiene.
Mission: document Firewall OT on YOUR OT lab
1) Name literacy rows on $OT_LAB. 2) Write NEVER list (no real-plant attacks, unauthorized OT scans, or exploit cookbooks). 3) chmod 600. Never scan or exploit real industrial networks.
Stuck? Ask Cyberlium AI Mentor
Ask Mentor: literacy on $OT_LAB — not attack recipes against live plants.
Knowledge Check
APPLY: Firewall OT on Cyberlium means:
Multiple choice
Knowledge Check
APPLY: True or False: Topic 38 includes ICS attack cookbooks against real plants.
True or False
Knowledge Check
APPLY: Firewall OT literacy on Cyberlium uses:
Multiple choice