Thread by @devops_tech

Mastering DNS Commands!

A Thread with examples of Linux commands commonly used in conjunction with DNS and DNS queries 👇

1/10: nslookup:
A versatile command-line tool for DNS queries. It provides information about domain names, IP addresses, and DNS records. #DNS #Linux

Example: nslookup example.com

2/10: dig:
Another powerful DNS query tool. It allows you to retrieve detailed information about DNS records, name servers, and perform advanced queries. #DNS #Linux

Example: dig A example.com

3/10: host:
A simple command for DNS lookups. It provides IP addresses and other DNS information. #DNS #Linux

Example: host example.com

4/10: whois:
Retrieves registration information for a domain name. It shows details about the domain's registrar, contact information, and more. #DNS #Linux

Example: whois example.com

5/10: nsupdate:
A command-line tool for making dynamic DNS updates. It allows you to add, modify, or delete DNS records dynamically. #DNS #Linux

Example: nsupdate -k keyfile.txt

6/10: named-checkzone:
Verifies the syntax and integrity of a DNS zone file. It helps identify errors before reloading the DNS server. #DNS #Linux

Example: named-checkzone /path/to/zonefileexample.com

7/10: rndc:
A management tool for BIND, a popular DNS server. It allows you to control and administer the DNS server from the command line. #DNS #Linux

Example: rndc reload

8/10: dnsmasq:
A lightweight DNS forwarder and DHCP server. It can be used to cache DNS queries and provide DNS services for a local network. #DNS #Linux

Example: dnsmasq --query-cache

9/10: systemd-resolve:
A command-line tool to resolve DNS queries using systemd's resolver. It provides DNS-related information and troubleshooting options. #DNS #Linux

Example: systemd-resolve --status

10/10: tcpdump:
A network packet analyzer that can be used to capture and analyze DNS traffic. It helps in troubleshooting DNS-related issues. #DNS #Linux

Example: tcpdump -i eth0 port 53

Time for some #Bonus again!

1/8: dig +trace:
Performs a DNS trace to show the complete path of DNS resolution. Useful for troubleshooting DNS issues and understanding the resolution process. #DNS #Linux #Advanced

Example: dig +trace example.com

2/8: dig +short:
Retrieves only the essential information, such as IP addresses or domain names, without additional details. Useful for scripting or getting concise output. #DNS #Linux #Advanced

Example: dig +short example.com

3/8: host -t:
Specifies a specific DNS record type to query. It allows you to retrieve specific information like MX records, TXT records, or SRV records. #DNS #Linux #Advanced

Example: host -t MX example.com

4/8: nslookup -type:
Similar to host -t, it lets you query for a specific record type using nslookup. Useful for obtaining particular DNS record types. #DNS #Linux #Advanced

Example: nslookup -type=NS example.com

5/8: nsupdate -v:
Enables verbose output for dynamic DNS updates using nsupdate. It provides detailed information about the update process. #DNS #Linux #Advanced

Example: nsupdate -v -k keyfile.txt

6/8: tcpdump -n:
Disables hostname resolution in tcpdump, showing IP addresses instead. Useful for capturing and analyzing DNS traffic without resolving hostnames. #DNS #Linux #Advanced

Example: tcpdump -n -i eth0 port 53

7/8: systemd-resolve --flush-caches:
Flushes the DNS resolver cache in systemd-resolve. Helps in clearing cached DNS entries and forcing fresh lookups. #DNS #Linux #Advanced

Example: systemd-resolve --flush-caches

8/8: rndc reconfig:
Reloads the configuration for BIND server without interrupting the service. Useful after modifying the DNS configuration files. #DNS #Linux #Advanced

Example: rndc reconfig

I hope this thread helps you explore and master DNS commands in Linux! Let me know if you have any further questions. #DNS #LinuxCommands

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