diff --git a/debian-live-config/check-iso.sh b/debian-live-config/check-iso.sh
index d42bf880..3529970a 100755
--- a/debian-live-config/check-iso.sh
+++ b/debian-live-config/check-iso.sh
@@ -80,6 +80,16 @@ if extract isolinux/isolinux.cfg && ! grep -qE '^timeout [1-9]' "${TMP}/isolinux
   FAILED=1
 fi
 
+# INSTALL.md and the onboarding wizard send people to wrolpi.local, which only
+# resolves if the WROLPi advertises its hostname over mDNS (avahi-daemon), and
+# only resolves on the WROLPi's own desktop with libnss-mdns.
+for pkg in avahi-daemon libnss-mdns; do
+  if ! grep -qE "^${pkg}(:[a-z0-9]+)?[[:space:]]" "${TMP}/filesystem.packages"; then
+    echo "ERROR: ${pkg} is not installed; wrolpi.local would not resolve." >&2
+    FAILED=1
+  fi
+done
+
 # The installer should default the hostname to wrolpi (wrolpi.local), via the
 # preseed live-build copies into each installer initrd.
 for initrd in install/initrd.gz install/gtk/initrd.gz; do
diff --git a/debian-live-config/config/includes.installer/preseed.cfg b/debian-live-config/config/includes.installer/preseed.cfg
index 5ba66eb9..32c7bc18 100644
--- a/debian-live-config/config/includes.installer/preseed.cfg
+++ b/debian-live-config/config/includes.installer/preseed.cfg
@@ -2,8 +2,8 @@
 # initrd, where d-i loads /preseed.cfg automatically.
 #
 # Default the hostname to wrolpi (Debian's default is "debian"), as on the live
-# session and the Pi: it names the TLS certificate, the SMB/NetBIOS share, and
-# the DHCP hostname a router may publish.  "seen false" keeps the question on
+# session and the Pi: Avahi advertises it as wrolpi.local, and it names the TLS
+# certificate, the SMB/NetBIOS share, and the DHCP hostname a router may publish.  "seen false" keeps the question on
 # screen, so it can still be changed; a hostname from DHCP takes precedence.
 d-i netcfg/get_hostname string wrolpi
 d-i netcfg/get_hostname seen false
diff --git a/debian-live-config/config/package-lists/wrolpi.list.chroot b/debian-live-config/config/package-lists/wrolpi.list.chroot
index 2300d4d1..eee4ae68 100644
--- a/debian-live-config/config/package-lists/wrolpi.list.chroot
+++ b/debian-live-config/config/package-lists/wrolpi.list.chroot
@@ -2,6 +2,7 @@ alsa-utils
 apt-transport-https
 aria2
 autoconf
+avahi-daemon
 bind9-dnsutils
 build-essential
 bzip2
@@ -50,6 +51,7 @@ libfreetype6-dev
 libgeos++-dev
 libgeos-dev
 libicu-dev
+libnss-mdns
 libproj-dev
 libreoffice
 libsqlite3-dev