DNS

Arch

Clear DNS cache:

sudo systemctl restart nscd

 

Debian

Clear DNS cache:

sudo service network-manager restart

 

Ubuntu 18 + Ubuntu 20

Show DNS server:

nmcli device show <interfacename> | grep DNS

 

Show statistics:

$ sudo systemd-resolve --statistics
DNSSEC supported by current servers: no

Transactions              
Current Transactions: 0   
  Total Transactions: 1036
                          
Cache                     
  Current Cache Size: 24  
          Cache Hits: 535 
        Cache Misses: 678 
                          
DNSSEC Verdicts           
              Secure: 0   
            Insecure: 0   
               Bogus: 0   
       Indeterminate: 0

 

Clear DNS cache:

sudo systemd-resolve --flush-caches

$sudo systemd-resolve --flush
$ sudo systemd-resolve --statistics
DNSSEC supported by current servers: no

Transactions              
Current Transactions: 0   
  Total Transactions: 1044
                          
Cache                     
  Current Cache Size: 2   
          Cache Hits: 535 
        Cache Misses: 686 
                          
DNSSEC Verdicts           
              Secure: 0   
            Insecure: 0   
               Bogus: 0   
       Indeterminate: 0

 

Ubuntu 22

Show DNS server(s):

$ resolvectl status
Global
       Protocols: -LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: uplink

Link 2 (eth0)
Current Scopes: DNS
     Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
   DNS Servers: fd:0:0:1::2

 

Flush DNS:

sudo resolvectl flush-caches

 

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