diff --git a/README.md b/README.md
index 55bd4a0..3ee8f84 100644
--- a/README.md
+++ b/README.md
@@ -35,11 +35,27 @@ The installer adds the official Zabbix apt repository, so minor/patch updates **
 ```bash
 sudo apt-get update
 sudo apt-get install --only-upgrade 'zabbix-proxy*' 'zabbix-sql-scripts'
-sudo systemctl restart zabbix-proxy-sqlite3   # or zabbix-proxy-mysql / -pgsql to match your DB
+sudo systemctl restart zabbix-proxy
 ```
 
 To move to a **new major version** (e.g. 7.0 → 7.4), the repository definition itself must change. Re-run the installer and enter the new version when prompted — it adds the new repo and upgrades in place.
 
+> The systemd unit is **`zabbix-proxy`** whichever database backend you chose — all three packages (`zabbix-proxy-sqlite3`, `-mysql`, `-pgsql`) ship the same `zabbix-proxy.service`. There is no `zabbix-proxy-sqlite3.service`.
+
+##### ICMP checks need fping
+
+The proxy uses `fping` for all `icmpping*` items, and Zabbix looks for it at `/usr/sbin/fping` by default — but Debian and Ubuntu install it to `/usr/bin/fping`. The installer now adds the package and writes the detected path into the config.
+
+Proxies built before that change have neither, so **every ping check behind them fails silently** while the log fills with `At least one of '/usr/sbin/fping', '/usr/sbin/fping6' must exist`. To check and fix an existing proxy:
+
+```bash
+command -v fping; grep -E '^Fping' /etc/zabbix/zabbix_proxy.conf   # both empty = affected
+
+sudo apt-get install -y fping
+printf '\nFpingLocation=/usr/bin/fping\nFping6Location=/usr/bin/fping6\n' | sudo tee -a /etc/zabbix/zabbix_proxy.conf
+sudo systemctl restart zabbix-proxy
+```
+
 ### Zabbix Agent
 
 Installs Zabbix Agent 2 on systems to be monitored. Configures it to connect to a local proxy.
diff --git a/install-zabbix-proxy-full.sh b/install-zabbix-proxy-full.sh
index db0c34f..3602534 100644
--- a/install-zabbix-proxy-full.sh
+++ b/install-zabbix-proxy-full.sh
@@ -300,7 +300,10 @@ log_ok "Repository added"
 # --- Install packages --------------------------------------------------------
 print_section "Installing Packages"
 
-PACKAGES=("$PROXY_PACKAGE" "zabbix-sql-scripts")
+# fping is required for ICMP checks (icmpping / icmppingsec / icmppingloss).
+# Without it every ping item on every host behind this proxy fails as
+# "unsupported", and the proxy logs the missing-binary error once a second.
+PACKAGES=("$PROXY_PACKAGE" "zabbix-sql-scripts" "fping")
 [[ "$DB_TYPE" == "MySQL" ]]      && PACKAGES+=("default-mysql-client")
 [[ "$DB_TYPE" == "PostgreSQL" ]] && PACKAGES+=("postgresql-client")
 
@@ -308,6 +311,22 @@ log_info "Installing: ${PACKAGES[*]}"
 DEBIAN_FRONTEND=noninteractive apt-get install -y -q "${PACKAGES[@]}"
 log_ok "Packages installed"
 
+# Locate fping rather than assuming a path: Debian/Ubuntu ship it in /usr/bin,
+# while Zabbix defaults to /usr/sbin/fping. Guessing wrong is exactly what makes
+# ICMP checks fail silently.
+FPING_BIN=$(command -v fping 2>/dev/null || true)
+FPING6_BIN=$(command -v fping6 2>/dev/null || true)
+FPING_BLOCK=""
+if [[ -n "$FPING_BIN" ]]; then
+    FPING_BLOCK="FpingLocation=${FPING_BIN}"
+    log_ok "fping found at $FPING_BIN"
+else
+    log_warn "fping not found — ICMP (ping) checks will not work on this proxy"
+fi
+if [[ -n "$FPING6_BIN" ]]; then
+    FPING_BLOCK="${FPING_BLOCK}${FPING_BLOCK:+$'\n'}Fping6Location=${FPING6_BIN}"
+fi
+
 # --- Database setup ----------------------------------------------------------
 if [[ "$DB_SETUP_NEEDED" == "true" ]]; then
     print_section "Database Setup"
@@ -451,6 +470,8 @@ ProxyBufferMode=hybrid
 ProxyMemoryBufferSize=64M
 
 Timeout=10
+
+${FPING_BLOCK}
 EOF
 
 chown root:zabbix "$PROXY_CONF"
@@ -459,6 +480,15 @@ log_ok "Configuration written to $PROXY_CONF"
 
 # --- Enable and start --------------------------------------------------------
 print_section "Starting Service"
+
+# Validate before starting so a config error reports the proxy's own message
+# rather than a bare systemd exit code.
+log_info "Validating configuration..."
+if ! CONFIG_TEST=$(zabbix_proxy -T -c "$PROXY_CONF" 2>&1); then
+    echo "$CONFIG_TEST" | sed 's/^/      /'
+    die "Configuration test failed — not starting the proxy"
+fi
+log_ok "Configuration valid"
 systemctl daemon-reload
 systemctl enable zabbix-proxy --quiet
 systemctl restart zabbix-proxy
diff --git a/install-zabbix-proxy.sh b/install-zabbix-proxy.sh
index da195b6..2b0fde4 100644
--- a/install-zabbix-proxy.sh
+++ b/install-zabbix-proxy.sh
@@ -245,9 +245,28 @@ log_ok "Repository added"
 
 # --- Install packages --------------------------------------------------------
 print_section "Installing Packages"
-log_info "Installing $PROXY_PACKAGE..."
-DEBIAN_FRONTEND=noninteractive apt-get install -y -q "$PROXY_PACKAGE"
-log_ok "Package installed"
+# fping is required for ICMP checks (icmpping / icmppingsec / icmppingloss).
+# Without it every ping item on every host behind this proxy fails as
+# "unsupported", and the proxy logs the missing-binary error once a second.
+log_info "Installing $PROXY_PACKAGE and fping..."
+DEBIAN_FRONTEND=noninteractive apt-get install -y -q "$PROXY_PACKAGE" fping
+log_ok "Packages installed"
+
+# Locate fping rather than assuming a path: Debian/Ubuntu ship it in /usr/bin,
+# while Zabbix defaults to /usr/sbin/fping. Guessing wrong is exactly what makes
+# ICMP checks fail silently.
+FPING_BIN=$(command -v fping 2>/dev/null || true)
+FPING6_BIN=$(command -v fping6 2>/dev/null || true)
+FPING_BLOCK=""
+if [[ -n "$FPING_BIN" ]]; then
+    FPING_BLOCK="FpingLocation=${FPING_BIN}"
+    log_ok "fping found at $FPING_BIN"
+else
+    log_warn "fping not found — ICMP (ping) checks will not work on this proxy"
+fi
+if [[ -n "$FPING6_BIN" ]]; then
+    FPING_BLOCK="${FPING_BLOCK}${FPING_BLOCK:+$'\n'}Fping6Location=${FPING6_BIN}"
+fi
 
 # --- Prepare SQLite directory ------------------------------------------------
 print_section "Preparing Database"
@@ -327,6 +346,8 @@ ProxyBufferMode=hybrid
 ProxyMemoryBufferSize=64M
 
 Timeout=10
+
+${FPING_BLOCK}
 EOF
 
 chown root:zabbix "$PROXY_CONF"
@@ -335,6 +356,16 @@ log_ok "Configuration written to $PROXY_CONF"
 
 # --- Enable and start --------------------------------------------------------
 print_section "Starting Service"
+
+# Validate before starting so a config error reports the proxy's own message
+# rather than a bare systemd exit code.
+log_info "Validating configuration..."
+if ! CONFIG_TEST=$(zabbix_proxy -T -c "$PROXY_CONF" 2>&1); then
+    echo "$CONFIG_TEST" | sed 's/^/      /'
+    die "Configuration test failed — not starting the proxy"
+fi
+log_ok "Configuration valid"
+
 systemctl daemon-reload
 systemctl enable zabbix-proxy --quiet
 systemctl restart zabbix-proxy