As more businesses move toward hybrid infrastructure, cybersecurity threats increase, and uptime expectations rise, network documentation has become a crucial component of M&A due diligence—especially in tech-enabled and data-driven businesses.

At Colonnade Advisors, we work with both buyers and sellers to assess the completeness and quality of a company’s IT documentation. A well-documented network environment signals operational maturity, improves transition planning, and reduces risk.

In this blog post, we outline the essential network documents that should be maintained and reviewed during diligence—and why they matter.

Core Infrastructure Documentation

Data Center & Disaster Recovery Documentation

This includes backup schedules, redundancy strategies, and failover mechanisms that ensure business continuity in the event of a data center failure or cyberattack.

✅ Why it matters: Buyers need to understand resilience—what happens if a server fails, a power outage hits, or ransomware locks the system down?

IP Addressing & Subnet Documentation

Records of IP ranges, VLANs, and subnet configurations for both internal and external networks.

✅ Why it matters: Clean documentation allows for scalability and troubleshooting. Sloppy or undocumented configurations signal potential chaos during integration.

Network Segmentation & VLAN Assignments

Logical network separation by department, function, or sensitivity level to limit exposure and improve security.

✅ Why it matters: Buyers assess whether your network is organized and secure—or wide open to lateral attacks.

WAN & LAN Architecture

Blueprints of local and wide-area networks: how offices, data centers, and cloud services connect.

✅ Why it matters: Helps identify redundancy, bottlenecks, and the complexity of integration post-acquisition.

Cloud Infrastructure & Hosting

Cloud Service Agreements

Contracts with AWS, Azure, Google Cloud, or other IaaS/PaaS providers. These should be stored under: 07 Legal & Regulatory / 01 Contracts & Agreements / 02 Vendor Agreements

✅ Why it matters: Agreements affect SLAs, data residency, and potential change-of-control clauses. They’re often overlooked in legal diligence.

Cloud & Hybrid Network Integration

Documentation of how on-premise and cloud environments are connected—VPC peering, VPN tunnels, routing tables.

✅ Why it matters: Hybrid complexity adds risk. Buyers need to understand connectivity, cost implications, and security exposure.

Cloud Networking Details

• Cloud VPC/Subnet configuration
• Cloud firewalls and security groups
• Cloud DNS/load balancers (e.g., Route53, Azure DNS)
  

Security & Access Control

Firewall Rules & VPN Architecture

Includes all inbound/outbound/NAT rules, plus VPN setups, access logs, and endpoint configurations.

Network Access Control (NAC)

Policies around 802.1X authentication, device compliance, and identity-based access control.

Intrusion Detection/Prevention (IDS/IPS)

Tools used, alerting thresholds, and incident response procedures.

✅ Why it matters: Buyers need to assess threat detection capabilities, segmentation, and whether there’s any exposure due to poor access control.

Operational Tools & Monitoring

Network Monitoring Systems (NMS)

Tools like SolarWinds, PRTG, or Nagios—including alerting logic and uptime thresholds.

Configuration Management & Change Logs

Version control and rollback procedures for routers, switches, and firewalls.

Performance Metrics & Historical Reports

SLAs, response time benchmarks, and outage history.

✅ Why it matters: Shows whether the team is proactive or reactive in managing infrastructure.

User & Device Access

• MAC address tables and device inventories
• Remote access policies (RDP, SSH, etc.)
• Guest network isolation and segmentation
  

Network Documentation Meta

Network Diagrams

Up-to-date physical and logical diagrams showing topology, connectivity, and data flows.

Runbooks / SOPs

Operational playbooks for outages, updates, or onboarding new hardware.

End-of-Life (EOL) Equipment List

List of legacy or unsupported devices that pose operational or security risk.

✅ Why it matters: EOL hardware increases risk and reduces flexibility post-close.

Final Thoughts: Why This Matters in M&A

A well-documented network:

• Reduces integration risk
• Increases buyer confidence
• Supports faster TSA planning
• Demonstrates operational maturity
  

If you’re preparing for a sale or investment, don’t wait for a buyer to ask for these materials—get ahead of it. Investing time in network documentation now will save time, protect value, and streamline diligence later.

📩 Need help preparing for technical diligence? Colonnade Advisors works with business owners and IT teams to prepare clean, defensible documentation for acquirers and investors.