Add listen-check

1 files changed, 37 insertions, 0 deletions

diff --git a/scripts/listen-check b/scripts/listen-check
new file mode 100755
index 0000000..45fe716
--- /dev/null
+++ b/scripts/listen-check
@@ -0,0 +1,37 @@
+#!/bin/sh
+#
+# Check that the host only listens on ports that are acceptable.
+
+set -e
+
+ports()
+{
+    netstat -nlap |
+    awk '
+        $6 == "LISTEN" {
+            n = split($7, a, /\//)
+            printf "%-10s %-20s %-20s %s\n", $1, $4, $5, a[2]
+        }'
+}
+
+
+case "$1" in
+    list)
+        ports
+        ;;
+    report)
+        temp="$(mktemp)"
+        ports > "$temp"
+        if diff -u /etc/listen-check.ok "$temp"
+        then
+            rm -f "$temp"
+        else
+            rm -f "$temp"
+            exit 1
+        fi
+        ;;
+    *)
+        echo "EEeek. Usage, man!" 1>&2
+        exit 1
+        ;;
+esac