MTU, PMTUD and the tunnel that worked yesterday
Path MTU discovery fails silently more often than it fails loudly. A short checklist for narrowing it down before you start blaming the application.
Notes on infrastructure, networking and the occasional yak shave.
Path MTU discovery fails silently more often than it fails loudly. A short checklist for narrowing it down before you start blaming the application.
Notes on scheduling verification restores instead of trusting exit codes, and why retention policy is a separate problem from backup policy.
openssl s_client still does most of what you need. What the flags
actually tell you, and the three things worth checking first.
Dual-stack is fine until one stack is worse than the other. Happy Eyeballs in practice, and the failure mode nobody notices for months.