{"version":"2.1.321","anchor":"ipv6-address-classification-returns-a-reason","canonical_anchor":"ipv6-address-classification-returns-a-reason","heading":"IPv6 private-address check now names the kind of address it found","tier":"internal","area":"Network","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321\/e\/ipv6-address-classification-returns-a-reason","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321","markdown":"### IPv6 private-address check now names the kind of address it found\n\nThe IPv6 address check now says why an address is special (unspecified, unique local or link local) and matches prefixes more strictly\n\n**Unclear.** It is not clear which features use this check, so the effect on what Claude Code allows or blocks is unknown.\n\n**What**\n\nClaude Code has a check that recognises special IPv6 addresses, such as ones that only work on a local network. It used to answer only yes or no. It now says which kind of address it found:\n\n- `unspecified`, the all-zeros address\n\n- `unique_local`, private addresses starting with fc or fd\n\n- `link_local`, addresses starting with fe80 that only work on the local network link\n\nAn ordinary address gets no answer. The fc, fd and fe80 checks now look only at the first group of the address, and only when that group is a full four characters long.\n\n**Why**\n\nThis is likely part of how Claude Code keeps requests away from private network addresses. The stricter prefix match makes it less likely that an address is put in the wrong category by mistake.\n\n- Area: Network\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 0\/5\n- Scope: individual\n- Heads-up: no"}