diff --git a/deploy/cache-me-outside.env.example b/deploy/cache-me-outside.env.example
index 384322f3d7b..608142e9887 100644
--- a/deploy/cache-me-outside.env.example
+++ b/deploy/cache-me-outside.env.example
@@ -112,3 +112,7 @@ CMO_CLUSTER_NODE_TIMEOUT=5000
 # CMO_BACKUP_DIR=/mnt/backups/cache-me-outside
 # CMO_BACKUP_KEEP=7
 # CMO_BACKUP_MAX_AGE_DAYS=30
+
+# Optional. Comma-separated CIDRs allowed to hit the published port.
+# Apply with deploy/ip-allowlist.sh (DOCKER-USER chain).
+# CMO_ALLOWED_CIDRS=10.0.0.0/8,203.0.113.7/32
diff --git a/deploy/ip-allowlist-test.sh b/deploy/ip-allowlist-test.sh
new file mode 100755
index 00000000000..4371832e83b
--- /dev/null
+++ b/deploy/ip-allowlist-test.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# Offline test for ip-allowlist.sh: no Docker, no root, no iptables.
+set -euo pipefail
+here="$(cd "$(dirname "$0")" && pwd)"
+tmp="$(mktemp -d)"; trap 'rm -rf "$tmp"' EXIT
+export CMO_ENV_FILE="$tmp/t.env"
+printf 'CMO_HOST_PORT=7000\n' >"$CMO_ENV_FILE"
+fail() { echo "FAIL: $*"; exit 1; }
+s="$here/ip-allowlist.sh"
+"$s" show | grep -q "not restricted" || fail show-empty
+"$s" set 10.0.0.0/8 203.0.113.7 >/dev/null || fail set
+grep -q '^CMO_ALLOWED_CIDRS=10.0.0.0/8,203.0.113.7/32$' "$CMO_ENV_FILE" || fail saved
+for bad in 0.0.0.0/0 300.1.1.1 1.2.3.4/33 abc; do "$s" set "$bad" 2>/dev/null && fail "accepted $bad"; done
+grep -q '^CMO_ALLOWED_CIDRS=10.0.0.0/8,203.0.113.7/32$' "$CMO_ENV_FILE" || fail kept-after-bad
+r="$("$s" rules)"
+grep -q -- "--dport 7000 -j CMO-ALLOW" <<<"$r" || fail port
+grep -q -- "-s 203.0.113.7/32 -j RETURN" <<<"$r" || fail allow
+[[ "$(tail -1 <<<"$r")" == "iptables -A CMO-ALLOW -j DROP" ]] || fail drop-last
+if [[ $EUID -ne 0 ]]; then "$s" apply 2>/dev/null && fail apply-nonroot; fi
+"$s" clear >/dev/null; "$s" rules 2>/dev/null && fail rules-after-clear
+echo "ip-allowlist tests passed"
diff --git a/deploy/ip-allowlist.sh b/deploy/ip-allowlist.sh
new file mode 100755
index 00000000000..18b5f7856fc
--- /dev/null
+++ b/deploy/ip-allowlist.sh
@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+# IP allow-list for the published Valkey port (plan item 33).
+# Valkey has no per-IP ACL, so this renders iptables rules for Docker's
+# DOCKER-USER chain (the chain Docker leaves for operators).
+#
+#   ./ip-allowlist.sh                     show the saved list
+#   ./ip-allowlist.sh set CIDR [CIDR...]  validate and save CMO_ALLOWED_CIDRS
+#   ./ip-allowlist.sh clear               remove the saved list (open again)
+#   ./ip-allowlist.sh rules               print the iptables commands
+#   ./ip-allowlist.sh apply               run them (root; nothing runs otherwise)
+# Rules live in their own chain CMO-ALLOW, so re-applying replaces them cleanly.
+set -euo pipefail
+source "$(dirname "${BASH_SOURCE[0]}")/lib.sh"
+
+cmo_valid_cidr() {
+    local c="$1" ip bits o
+    [[ "$c" == */* ]] || c="$c/32"
+    ip="${c%/*}"; bits="${c#*/}"
+    [[ "$bits" =~ ^[0-9]{1,2}$ ]] && (( bits <= 32 )) || return 1
+    [[ "$ip" =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]] || return 1
+    IFS=. read -ra o <<<"$ip"
+    for x in "${o[@]}"; do (( 10#$x <= 255 )) || return 1; done
+    [[ "$c" != 0.0.0.0/0 ]] || return 1
+    printf '%s\n' "$c"
+}
+
+cmo_allow_save() {
+    local file="$1" value="$2"
+    touch "$file"
+    if grep -q '^CMO_ALLOWED_CIDRS=' "$file"; then
+        sed -i "s|^CMO_ALLOWED_CIDRS=.*|CMO_ALLOWED_CIDRS=${value}|" "$file"
+    else
+        printf 'CMO_ALLOWED_CIDRS=%s\n' "$value" >>"$file"
+    fi
+}
+
+cmo_allow_rules() {
+    local port="$1" list="$2" c
+    echo "iptables -N CMO-ALLOW 2>/dev/null || iptables -F CMO-ALLOW"
+    echo "iptables -C DOCKER-USER -p tcp --dport ${port} -j CMO-ALLOW 2>/dev/null || iptables -I DOCKER-USER -p tcp --dport ${port} -j CMO-ALLOW"
+    echo "iptables -A CMO-ALLOW -m conntrack --ctstate ESTABLISHED,RELATED -j RETURN"
+    for c in ${list//,/ }; do echo "iptables -A CMO-ALLOW -s ${c} -j RETURN"; done
+    echo "iptables -A CMO-ALLOW -j DROP"
+}
+
+if [[ "${CMO_ALLOW_LIB:-}" == 1 ]]; then return 0 2>/dev/null || exit 0; fi
+
+file="$(cmo_env_path)"
+saved="$( (grep '^CMO_ALLOWED_CIDRS=' "$file" 2>/dev/null || true) | tail -1 | cut -d= -f2-)"
+port="$( (grep '^CMO_HOST_PORT=' "$file" 2>/dev/null || true) | tail -1 | cut -d= -f2-)"
+port="${port:-6379}"
+
+case "${1:-show}" in
+    show) echo "${saved:-(empty: port ${port} is not restricted)}" ;;
+    set)
+        shift; [[ $# -gt 0 ]] || { echo "give at least one CIDR" >&2; exit 1; }
+        out=()
+        for c in "$@"; do v="$(cmo_valid_cidr "$c")" || { echo "bad CIDR: $c" >&2; exit 1; }; out+=("$v"); done
+        joined="$(IFS=,; echo "${out[*]}")"
+        cmo_allow_save "$file" "$joined"
+        echo "saved: $joined (run '$0 apply' as root to enforce)" ;;
+    clear) cmo_allow_save "$file" ""; echo "cleared (run 'iptables -F CMO-ALLOW' as root to open the port)" ;;
+    rules) [[ -n "$saved" ]] || { echo "no list saved" >&2; exit 1; }; cmo_allow_rules "$port" "$saved" ;;
+    apply)
+        [[ -n "$saved" ]] || { echo "no list saved" >&2; exit 1; }
+        [[ $EUID -eq 0 ]] || { echo "apply needs root" >&2; exit 1; }
+        cmo_allow_rules "$port" "$saved" | bash -e
+        echo "enforced on port ${port}: ${saved}" ;;
+    *) sed -n 2,11p "$0"; exit 1 ;;
+esac
diff --git a/docs/ci/cmo-ip-allowlist-test.patch b/docs/ci/cmo-ip-allowlist-test.patch
new file mode 100644
index 00000000000..4f48441dcaf
--- /dev/null
+++ b/docs/ci/cmo-ip-allowlist-test.patch
@@ -0,0 +1,12 @@
+--- a/.github/workflows/cmo-ci.yml
++++ b/.github/workflows/cmo-ci.yml
+@@ -28,6 +28,9 @@
+       - name: Build server
+         run: make -j"$(nproc)" SERVER_CFLAGS='-Werror'
+ 
++      - name: IP allow-list offline test
++        run: deploy/ip-allowlist-test.sh
++
+       - name: Run a fast Valkey test subset
+         run: |
+           # introspection is omitted: its forkless-bgsave case is timing-sensitive