OpsCheck Blog

Practical guides for system administrators, hosting engineers, and network professionals.

Network

CIDR Overlap in VPN and Private Networks: How to Find Bad Subnet Planning

CIDR overlap between your office LAN, VPN subnets, and cloud VPCs causes subtle routing failures. Learn how to audit and fix overlapping address space.

May 23, 2026 · 5 min read Read

IPv6

IPv6 Works for Some Users but Fails for Others: How to Diagnose It

When IPv6 connectivity works for some visitors but not others, the root cause is usually asymmetric path MTU, broken tunnel brokers, or misconfigured DNS. Diagnose it systematically.

May 22, 2026 · 6 min read Read

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