63 lines
1.8 KiB
Bash
63 lines
1.8 KiB
Bash
#!/usr/bin/env bash
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# netcheck.sh — Diagnose DNS / TLS / Route problems for a given target
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TARGET=${1:-fonts.gstatic.com} # 默认检测 fonts.gstatic.com，也可自定义
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PROXY=${https_proxy:-""}
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if [ -z "$1" ]; then
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echo "Usage: $0 <domain>"
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echo "Example: $0 accounts.google.com"
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echo
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echo "No argument supplied, using default target: $TARGET"
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fi
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echo "=== 🌐 Network Diagnostic for $TARGET ==="
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echo "Time: $(date)"
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echo
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echo "1️⃣ Checking DNS resolution..."
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dig +short "$TARGET" || nslookup "$TARGET"
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echo
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IP=$(dig +short "$TARGET" | grep -m1 -Eo '([0-9]{1,3}\.){3}[0-9]{1,3}')
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if [ -z "$IP" ]; then
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echo "❌ DNS failed — cannot resolve $TARGET"
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exit 1
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fi
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echo "✅ DNS OK → $TARGET resolved to $IP"
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echo
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echo "2️⃣ Checking basic connectivity..."
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ping -c 3 -W 2 "$IP" >/dev/null 2>&1 && echo "✅ Ping reachable ($IP)" || echo "⚠️ Ping not reachable (may be ICMP blocked)"
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echo
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echo "3️⃣ Checking route path..."
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traceroute -m 15 -w 2 "$IP" || echo "⚠️ Traceroute failed — possibly blocked or proxied"
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echo
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echo "4️⃣ Testing HTTPS handshake (TLS)..."
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if [ -n "$PROXY" ]; then
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echo "Using proxy: $PROXY"
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fi
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curl -v --connect-timeout 10 -4 -I "https://$TARGET" 2>&1 | egrep "Trying|Connected|SSL|error|subject|issuer|HTTP"
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RC=$?
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echo
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if [ $RC -eq 0 ]; then
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echo "✅ TLS handshake successful — outbound HTTPS working"
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else
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echo "❌ TLS handshake failed — outbound 443 likely filtered or intercepted"
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fi
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echo
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echo "5️⃣ Summary:"
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if [ $RC -ne 0 ]; then
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echo "→ Problem most likely in:"
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echo " • DNS (if Step 1 failed)"
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echo " • Firewall/Proxy (if Step 2/3 OK but Step 4 fails)"
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echo " • TLS interception (if Step 4 shows certificate mismatch)"
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else
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echo "✅ Everything looks fine — network path and TLS normal"
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fi
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