diff --git a/Dockerfile.debian b/Dockerfile.debian
index ff8fb04d..5b4c1823 100644
--- a/Dockerfile.debian
+++ b/Dockerfile.debian
@@ -5,6 +5,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   autoconf \
   autoconf-archive \
   automake \
+  ca-certificates \
   expect \
   gcc \
   git \
diff --git a/Dockerfile.fedora b/Dockerfile.fedora
index 889f75eb..3838cde2 100644
--- a/Dockerfile.fedora
+++ b/Dockerfile.fedora
@@ -9,6 +9,7 @@ RUN dnf install -y \
   autoconf-archive \
   automake \
   awk \
+  ca-certificates \
   expect-devel \
   gcc \
   git \
diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index 53761022..5c353194 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -6,6 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   autoconf \
   autoconf-archive \
   automake \
+  ca-certificates \
   expect \
   gcc \
   git \
diff --git a/ci-build.sh b/ci-build.sh
index 82ff76ff..e0e2a551 100755
--- a/ci-build.sh
+++ b/ci-build.sh
@@ -144,7 +144,7 @@ do
     echo
 
     # shellcheck disable=SC2086
-    ./configure $features $*
+    ./configure -C $features $*
 
     $MAKE CC="${CC}"
     $MAKE check