FROM soap # Install OS CA tooling + mono cert sync tool (Debian/Ubuntu-based images) RUN apt-get update \ && apt-get install -y --no-install-recommends ca-certificates mono-utils \ && rm -rf /var/lib/apt/lists/* # Add your internal CA chain as a trusted CA bundle COPY local-config/LandmarkRootCA.crt /usr/local/share/ca-certificates/LandmarkRootCA.crt COPY local-config/LandmarkIssuingCA1.crt /usr/local/share/ca-certificates/LandmarkIssuingCA1.crt # Update OS trust + sync into Mono trust RUN update-ca-certificates \ && cert-sync /etc/ssl/certs/ca-certificates.crt # (Optional) Point SSL_CERT_FILE at the system bundle Mono is most likely to use ENV SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt