openSUSE:Post-mortem-20241112

• What/Problem: openSUSE wiki and other sites were disfunctional
• When: 2024-11-12 02:40 to 05:18 UTC, 2024-11-11 01:30 to 08:30 (and a few times before that, known issue that did not gain much traction before)
• Why: We identified a number of contributing issues:
  • some relevant IPv6-NDP neighbor-solicit packets were blocked by the firewall
  • It broke at a time when admin availability was low, so debugging was delayed.
  • details are in https://progress.opensuse.org/issues/168487