cloud engineer
Handy little script to see if nameserver is on an array.
#!/bin/bash declare -a servers=("127.0.0.53" "127.0.0.52" "127.0.0.51") client=$(cat /etc/resolv.conf | grep nameserver) for i in "${servers[@]}" do if [[ $client =~ $i ]] then using_unbound="true" break else using_unbound="false" fi done echo $using_unbound "|" $client |
#!/bin/bash declare -a servers=("127.0.0.53" "127.0.0.52" "127.0.0.51") client=$(cat /etc/resolv.conf | grep nameserver) for i in "${servers[@]}" do if [[ $client =~ $i ]] then using_unbound="true" break else using_unbound="false" fi done echo $using_unbound "|" $client
Here’s how to troubleshoot nameservers with dig.
dig hostname dig domain.com |
dig hostname dig domain.com
To test a specific nameserver.
dig @nameserver hostname dig @nameserver ip-address |
dig @nameserver hostname dig @nameserver ip-address
Other options.
dig hostname.domain.com +short dig hostname.domain.com +noall +answer dig @nameserver MX domain.com dig @nameserver AAAA domain.com |
dig hostname.domain.com +short dig hostname.domain.com +noall +answer dig @nameserver MX domain.com dig @nameserver AAAA domain.com
Resolv.conf is a computer file used by various operating systems as a DNS resolver. The file is in plain text. It’s usually generated by the system administrator or a network program. The file is located in the /etc/ directory and contains the search domain as well a list of nameservers.
Here’s an example of the /etc/resolv.conf file.
search domain.com local.lan nameserver 1.1.1.1 nameserver 8.8.8.8 nameserver 9.9.9.9 |
search domain.com local.lan nameserver 1.1.1.1 nameserver 8.8.8.8 nameserver 9.9.9.9
If you have problems resolving domain names, check this file first.