Floke
f2394e322f
- Updated 'duckdns_setup.md' with critical instructions for configuring FritzBox DNS Rebind Protection to enable internal access (NAT Loopback). - Added steps for clearing client-side DNS cache (Windows). - Included Cloudflare DNS switch in documentation reflecting recent monitor script changes.
60 lines
1.9 KiB
Bash
60 lines
1.9 KiB
Bash
#!/bin/sh
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# DNS-Monitor v2.0 - Optimized for Synology/Docker stability
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# Monitoring: Public IP vs. Cloudflare DNS (1.1.1.1)
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# Ensure dependencies
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if ! command -v dig >/dev/null 2>&1; then
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apk add --no-cache bind-tools
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fi
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if ! command -v curl >/dev/null 2>&1; then
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apk add --no-cache curl
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fi
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echo "[DNS-MONITOR] Service started. Monitoring $SUBDOMAINS via Cloudflare (1.1.1.1)"
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while true; do
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# 1. Fetch Public IP
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PUBLIC_IP=$(curl -s -4 -m 15 https://api.ipify.org)
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if [ -z "$PUBLIC_IP" ]; then
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PUBLIC_IP="Error: Public IP fetch failed"
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fi
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# Get the first subdomain to check
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FIRST_SUB=$(echo $SUBDOMAINS | cut -d',' -f1)
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if [ -z "$FIRST_SUB" ]; then
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echo "[DNS-MONITOR] No subdomain found in env var SUBDOMAINS"
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else
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FULL_DOMAIN="${FIRST_SUB}.duckdns.org"
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# 2. Resolve Global IP (Cloudflare 1.1.1.1)
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# Using +time and +tries for high reliability on shaky connections
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GLOBAL_IP=$(dig @1.1.1.1 +short +time=8 +tries=3 A "$FULL_DOMAIN" | head -n 1)
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# 3. Resolve Local IP (Internal Docker/Host DNS)
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# This checks if the local cache is still stuck
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LOCAL_IP=$(dig +short +time=8 +tries=3 A "$FULL_DOMAIN" | head -n 1)
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if [ -z "$GLOBAL_IP" ]; then GLOBAL_IP="Unresolved"; fi
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if [ -z "$LOCAL_IP" ]; then LOCAL_IP="Unresolved"; fi
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TIMESTAMP=$(date '+%Y-%m-%d %H:%M:%S')
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# Status Logic
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if [ "$PUBLIC_IP" = "$GLOBAL_IP" ]; then
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STATUS="OK"
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elif [ "$GLOBAL_IP" = "Unresolved" ]; then
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STATUS="NETWORK_WAIT" # Network or DNS provider issue, not necessarily DuckDNS
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else
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STATUS="ALERT" # Public IP != Global IP (DuckDNS update missing or zombie active)
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fi
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# Log entry
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echo "[$TIMESTAMP] [$STATUS] Pub: $PUBLIC_IP | CF: $GLOBAL_IP | Loc: $LOCAL_IP"
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fi
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# Check every 5 minutes
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sleep 300
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done |