How to Use the Command 'dog' (with Examples)
The ‘dog’ command line tool is a versatile DNS lookup utility renowned for its colorful output and support for contemporary DNS protocols like DNS-over-TLS and DNS-over-HTTPS. It can provide results in different formats, such as JSON, making it suitable for integration in various applications or troubleshooting tasks. As internet users and developers often need to perform DNS queries for different purposes, ‘dog’ offers an efficient and user-friendly solution for accessing these records.
Use Case 1: Lookup the IP(s) Associated with a Hostname (A Records)
Code:
dog example.com
Motivation: Performing a DNS lookup to find the IP address associated with a hostname is one of the most common uses of DNS queries. This is particularly useful for network administrators, security analysts, web developers, or anyone needing to diagnose connectivity problems or verify the association between a domain name and its server’s IP address.
Explanation:
dog: The command to invoke the DNS lookup utility.example.com: The domain name for which you want to find the associated IP address (A records). A records are the most basic type of DNS data, mapping domain names to IP addresses.
Example Output:
example.com. 1259 IN A 93.184.216.34
This output indicates that ’example.com’ maps to the IP address 93.184.216.34.
Use Case 2: Query the MX Records Type Associated with a Given Domain Name
Code:
dog example.com MX
Motivation: Mail Exchange (MX) records are essential in directing email traffic on the internet. Network administrators and system engineers often need to check MX records to troubleshoot email delivery issues, verify email server addresses, or configure mail servers.
Explanation:
dog: Initiates the DNS lookup utility.example.com: The domain for which you want to query MX records.MX: Specifies that the query is for Mail Exchange records, which outline the email server responsible for receiving emails on behalf of the domain.
Example Output:
example.com. 3600 IN MX 10 mail.example.com.
This output indicates that the mail server for ’example.com’ is ‘mail.example.com’ with a preference number of 10.
Use Case 3: Specify a Specific DNS Server to Query (e.g., Cloudflare)
Code:
dog example.com MX @1.1.1.1
Motivation: Sometimes, different DNS servers return different results for the same query due to reasons such as caching and propagation delays. By specifying a particular DNS server, you can bypass the default DNS servers, verify DNS propagation, or troubleshoot DNS issues from another location.
Explanation:
dog: The command for the DNS lookup tool.example.com: The domain name to query.MX: Indicates that the Mail Exchange records are being requested.@1.1.1.1: Specifies Cloudflare’s DNS server as the source of the DNS query.
Example Output:
example.com. 3600 IN MX 10 mail.cloudflare.com.
The result shows the MX record with Cloudflare as the DNS server, potentially differing from other DNS servers.
Use Case 4: Query Over TCP Rather Than UDP
Code:
dog example.com MX @1.1.1.1 --tcp
Motivation: Queries over TCP are often necessary for resolving DNS queries involving large responses or for ensuring the reliability of data transfer, as TCP is a connection-oriented protocol that guarantees delivery. Additionally, some network configurations prefer TCP for DNS for added security.
Explanation:
dog: The command for DNS lookup.example.com: The domain to query.MX: Referencing the Mail Exchange records.@1.1.1.1: Designating Cloudflare’s DNS server as the target.--tcp: Forces the query to use TCP, rather than the default UDP.
Example Output:
example.com. 3600 IN MX 10 mail.tcp.cloudflare.com.
The output shows querying MX records using TCP with Cloudflare’s DNS server.
Use Case 5: Query the MX Records Type Associated with a Domain Name Over TCP Using Explicit Arguments
Code:
dog --query example.com --type MX --nameserver 1.1.1.1 --tcp
Motivation: This use case exemplifies using explicit arguments to increase clarity, precision, or even script automation. By fully specifying the parameters, it’s easier to reuse this command in automated scripts or documentation where clarity is paramount.
Explanation:
dog: Invokes the DNS lookup utility.--query example.com: Defines the domain name to query.--type MX: Indicates that the Mail Exchange records are being requested.--nameserver 1.1.1.1: Specifies Cloudflare’s DNS server.--tcp: Directs the command to use TCP for the query.
Example Output:
example.com. 3600 IN MX 10 explicit.mail.cloudflare.com.
Consistency in output, fostering confidence in accurate MTX records obtained via specified servers and methods.
Use Case 6: Lookup the IP(s) Associated with a Hostname (A Records) Using DNS Over HTTPS (DoH)
Code:
dog example.com --https @https://cloudflare-dns.com/dns-query
Motivation: DNS over HTTPS (DoH) ensures privacy and integrity of DNS queries by encrypting the data between the client and DNS server. This is crucial in environments where privacy is a priority, or when operating over insecure networks.
Explanation:
dog: Runs the DNS lookup command.example.com: Specifies the domain for which to look up the A records.--https: Indicates that the query should use DNS-over-HTTPS.@https://cloudflare-dns.com/dns-query: Points to Cloudflare’s DNS server utilizing their DNS-over-HTTPS endpoint.
Example Output:
example.com. 3600 IN A 93.184.216.34
Query results indicating successful retrieval of IP address via DNS-over-HTTPS, showcasing secured DNS resolution.
Conclusion:
The ‘dog’ command is a versatile DNS lookup utility that supports a variety of protocols and customization options. Each use case showcased above underscores ‘dog’s’ utility in different scenarios, from basic DNS queries to more advanced configurations like using specific DNS servers, querying over TCP, and employing DNS-over-HTTPS, ensuring both flexibility and security. Whether for troubleshooting, development, or automated scripting, ‘dog’ provides a robust toolset for navigating and managing DNS queries effectively.
