“Kdig” is an advanced DNS (Domain Name System) lookup utility that provides extensive functionality for querying DNS servers and retrieving domain-related information. It is part of the Knot DNS suite, which is an open-source high-performance DNS server and resolver developed by CZ.NIC Labs. Kdig offers a command-line interface for performing various DNS operations and gathering detailed information about domain names and their associated records.
Here are some key features and functionalities of Kdig:
- DNS Querying: Kdig allows users to perform DNS queries against DNS servers to retrieve information about domain names, such as IP addresses, mail exchange (MX) records, name server (NS) records, and more. Users can specify the type of DNS record they want to query, such as A, AAAA, MX, TXT, PTR, etc.
- Advanced Query Options: Kdig supports advanced query options and parameters that enable users to customize their DNS queries. Users can specify the DNS server to query, set the query timeout, specify the DNS protocol (UDP or TCP), enable DNSSEC validation, and control the query recursion behavior.
- DNSSEC Support: Kdig provides support for DNSSEC (Domain Name System Security Extensions), which is a set of security extensions designed to add cryptographic authentication to DNS responses. Users can enable DNSSEC validation when performing DNS queries to ensure the integrity and authenticity of DNS data.
- Verbose Output: Kdig produces verbose output that includes detailed information about DNS responses, such as the response code, response time, authoritative name servers, DNSSEC validation status, and more. This allows users to inspect and analyze DNS responses thoroughly.
- Batch Mode: Kdig supports batch mode operation, allowing users to specify multiple DNS queries in a single command. Users can provide a list of domain names or DNS records to query, and Kdig will perform the queries sequentially, displaying the results for each query.
- Output Formatting: Kdig provides flexible output formatting options that allow users to customize the presentation of DNS query results. Users can choose from various output formats, such as human-readable text, machine-readable JSON, or XML, depending on their preferences and use cases.
- Documentation and Resources: Kdig is well-documented, with comprehensive man pages and documentation available online. The documentation covers usage instructions, command-line options, query syntax, and examples of common DNS lookup scenarios. Additionally, users can find tutorials, guides, and troubleshooting resources to help them effectively use Kdig.
kdig Command Examples
1. Lookup the IP(s) associated with a hostname (A records):
# kdig [example.com]
2. Specify a specific DNS server to query (e.g. Google DNS):
# kdig [example.com] @[8.8.8.8]
3. Query a specific DNS record type associated with a given domain name:
# kdig [example.com] [A|AAAA|NS|SOA|DNSKEY|ANY]
4. Lookup the IP(s) associated with a hostname (A records) using DNS over TLS (DoT):
# kdig -d @[8.8.8.8] +tls-ca +tls-host=[dns.google] [example.com]
5. Lookup the IP(s) associated with a hostname (A records) using DNS over HTTPS (DoH):
# kdig -d @[1.1.1.1] +https +tls -hostname=[1dot1dot1dot1.cloudflare-dns.com] [example.com]
Summary
Overall, Kdig is a powerful and versatile DNS lookup utility that provides advanced functionality for querying DNS servers and retrieving domain-related information. Whether performing basic DNS lookups, troubleshooting DNS issues, or conducting DNSSEC validation, Kdig offers the tools and capabilities needed to effectively work with DNS data.