diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index bd3cf72a4..52af2635c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -34,6 +34,7 @@ jobs:
             meson \
             libavahi-client-dev \
             libboost-dev \
+            libc-ares-dev \
             libsystemd-dev \
             libdbus-1-dev \
             libcap-dev \
diff --git a/README.rst b/README.rst
index dbf6367e6..cc5aff30c 100644
--- a/README.rst
+++ b/README.rst
@@ -33,6 +33,7 @@ You need:
 
 Optional dependencies:
 
+- `c-ares <https://c-ares.org/>`__
 - `libcurl <https://curl.haxx.se/>`__
 - `libpq <https://www.postgresql.org/>`__
 - `libsodium <https://www.libsodium.org/>`__