Re: Seeing full FQDN in chronyc output

like many programs, chrony just does a reverse-lookup of the IP address, which
results in a FQDN name (only) when a PTR record for the address is available in DNS.

When you want to have that info you can use the chronyc -n sources command, and
then parse the output to extract the IP addresses and do a reverse lookup on them,
and get the result with the length that you want.

I use this script to perform such lookups.  I saved it as /usr/local/bin/ip2host and then
you can use: chronyc -n sources | ip2host

Of course it destroys the layout of the output.

Rob

#!/usr/bin/perl -w

my ($ip,$host);
my @fields;

while (<>) {
    chomp;

    @fields = split /(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/, $_;

    foreach $ip (@fields) {
        if ($ip =~ m!^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$!) {
            if (defined $cache{$ip}) {
                $host = $cache{$ip};
            } else {                                                            
                $host = (gethostbyaddr(pack('C4',$1,$2,$3,$4),2))[0] || $ip;    
                $cache{$ip} = $host;                                           
            }                                                                   
                                                                                
            if ($ip ne $host) {                                                 
                $ip = $host.'['.$ip.']';                                        
            }                                                                   
        }                                                                       
    }                                                                           
                                                                                
    print @fields,"\n";                                                         
}                                                                         

On 2024-06-26 20:37, Mike Hall wrote:
> Info in the /etc/chrony.conf file has IP addresses for the time servers.
> "chronyc -n sources" seems to be providing the IP addresses only.
>
> Should have mentioned in initial post that this version is the current
> RHEL 8 version.  -- version 4.5 (+READLINE +SECHASH +IPV6 +DEBUG)
>
> On Wed, Jun 26, 2024 at 2:33 PM Josef 'Jeff' Sipek <[email protected]> wrote:
>
>     On Wed, Jun 26, 2024 at 14:29:07 -0400, Mike Hall wrote:
>     ...
>     > Are there any other versions of the command that
>     > would provide a full FQDN, and preferably all FQDN names.
>
>     Does 'chronyc -n sources' do what you want?  See the manpage for a full
>     description.
>
>     Jeff.
>
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>
> -- 
> Michael "Mike" Hall, Sr.  
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