73 lines
2.7 KiB
Python
Executable File
73 lines
2.7 KiB
Python
Executable File
#!/usr/bin/env python3
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import argparse
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import socket
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import sys
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import time
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import dns.message
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import dns.query
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def resolve_dns_server_ip(server):
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try:
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ip_address = socket.getaddrinfo(server, None, family=socket.AF_INET)[0][4][0]
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except socket.gaierror:
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raise ValueError("Failed to resolve DNS server domain")
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return ip_address
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def main():
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parser = argparse.ArgumentParser(description='Check DNS-over-TLS connectivity and response time')
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parser.add_argument('-c', '--critical', type=float, default=500, help='Critical threshold for response time in milliseconds (default: 500)')
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parser.add_argument('-w', '--warning', type=float, default=300, help='Warning threshold for response time in milliseconds (default: 300)')
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parser.add_argument('-d', '--domain', type=str, default='google.com', help='Domain to resolve (default: google.com)')
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parser.add_argument('-s', '--server', type=str, required=True, help='DNS server address')
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parser.add_argument('-p', '--port', type=int, default=853, help='Port to use for DNS-over-TLS (default: 853)')
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args = parser.parse_args()
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try:
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server_ip = resolve_dns_server_ip(args.server)
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except ValueError as e:
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print(f'CRITICAL - {str(e)}')
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sys.exit(2)
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error_message = None
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query = dns.message.make_query(args.domain, dns.rdatatype.A)
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start_time = time.time()
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try:
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response = dns.query.tls(query, server_ip, port=args.port, timeout=args.critical)
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except dns.exception.SyntaxError:
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error_message = "invalid IP address or domain name"
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except dns.exception.Timeout:
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error_message = "the DNS operation timed out"
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except Exception as e:
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error_message = e
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if error_message:
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print(f'CRITICAL - DNS-over-TLS query failed: {error_message}')
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sys.exit(2)
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response_time = time.time() - start_time
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response_time_ms = int(response_time * 1000)
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if response.rcode() != dns.rcode.NOERROR:
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print(f'CRITICAL - DNS query returned error: {dns.rcode.to_text(response.rcode())}')
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sys.exit(2)
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resolved_ips = [str(rr.address) for rr in response.answer[0] if rr.rdtype == dns.rdatatype.A]
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perfdata = f'Resolved IPs: {", ".join(resolved_ips)} | response_time={response_time_ms}ms;{args.warning};{args.critical};0;'
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if response_time_ms >= args.critical:
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print(f'CRITICAL - DNS-over-TLS response time: {response_time:.2f} sec.')
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sys.exit(2)
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elif response_time_ms >= args.warning:
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print(f'WARNING - DNS-over-TLS response time: {response_time:.2f} sec.')
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sys.exit(1)
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else:
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print(f'OK - DNS-over-TLS response time: {response_time:.2f} sec. {perfdata}')
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sys.exit(0)
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if __name__ == '__main__':
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main()
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