Modern business networks span offices, cloud services, and remote users. Good network security limits unnecessary connectivity and provides the visibility needed to investigate issues.
Segment the network
Separate user devices, servers, guest Wi-Fi, printers and IoT devices, and management interfaces into different zones. Segmentation limits how far an attacker or malware can move if one device is compromised.
Adopt a default-deny approach
Firewall rules should allow only the traffic that is required, with everything else denied. Document the purpose and owner of each rule and review rules periodically to remove those no longer needed.
Secure remote access
Require multi-factor authentication for VPNs and remote access tools, keep remote access appliances updated, and avoid exposing administrative interfaces directly to the internet.
Harden wireless networks
Use current wireless security standards, separate guest access from business systems, and change default credentials on access points and controllers.
Protect DNS and email
Configure email authentication records such as SPF, DKIM, and DMARC to make domain impersonation harder, and consider DNS filtering to block access to known malicious domains.
Collect useful logs
Firewall, VPN, DNS, and authentication logs are valuable during investigations. Retain them centrally for a defined period and ensure clocks are synchronized.
Key takeaways
- Segment by function and trust level.
- Review firewall rules regularly.
- Protect remote access with MFA.
- Centralize and retain key logs.
This article provides general information and is not a substitute for advice specific to your organization.