fix(fc-llm-bridge): set dnsConfig ndots=2 to prevent CoreDNS wildcard hijack

Pods in this cluster inherit ndots=5. External FQDNs with <5 dots (like
api.anthropic.com) are expanded through the search path first, and the 4th
suffix `api.anthropic.com.iamworkin.lan` matches CoreDNS' `template IN A
iamworkin.lan` wildcard — resolves to Traefik VIP 10.0.56.200. TLS connect
lands on Traefik's default cert and the AnthropicClient rejects with
RemoteCertificateNameMismatch/RemoteCertificateChainErrors.

Setting ndots=2 makes the resolver try the bare FQDN first (3 dots in
api.anthropic.com), so the search path never fires.

Reference: memory feedback_coredns_ndots_template_collision. Wider follow-up:
the CoreDNS template plugin should add fallthrough for external public suffixes,
so every FC service calling external HTTPS APIs stops hitting this trap.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Andrew Stoltz
2026-04-23 09:42:17 -05:00
parent 11c48bef30
commit 4cd5806fd0

View File

@@ -207,6 +207,17 @@ spec:
port: 8080 port: 8080
initialDelaySeconds: 15 initialDelaySeconds: 15
periodSeconds: 30 periodSeconds: 30
# Lower ndots so external FQDNs like api.anthropic.com are tried BEFORE
# the ndots:5 default expands them through the cluster search path, which
# includes iamworkin.lan. CoreDNS has a `template IN A iamworkin.lan`
# wildcard that answers `api.anthropic.com.iamworkin.lan` with the
# Traefik VIP, which then serves a TRAEFIK-DEFAULT-CERT TLS cert and
# breaks egress to the real Anthropic API (memory:
# feedback_coredns_ndots_template_collision, generalized to external DNS).
dnsConfig:
options:
- name: ndots
value: "2"
volumes: volumes:
- name: data - name: data
persistentVolumeClaim: persistentVolumeClaim: