Reviewed-by: Peter Müller <peter.mueller(a)ipfire.org>

> Fixes #12349.
> 
> Signed-off-by: Stefan Schantl <stefan.schantl(a)ipfire.org>
> ---
>  config/cfgroot/ids-functions.pl | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/config/cfgroot/ids-functions.pl b/config/cfgroot/ids-functions.pl
> index 5bc3e77ec..f124b12be 100644
> --- a/config/cfgroot/ids-functions.pl
> +++ b/config/cfgroot/ids-functions.pl
> @@ -718,13 +718,28 @@ sub generate_dns_servers_file() {
>  	# Get the used DNS servers.
>  	my @nameservers = &General::get_nameservers();
>  
> +	# Get network settings.
> +	my %netsettings;
> +	&General::readhash("${General::swroot}/ethernet/settings", \%netsettings);
> +
>  	# Format dns servers declaration.
>  	my $line = "";
>  
>  	# Check if the system has configured nameservers.
>  	if (@nameservers) {
> +		# Add the GREEN address as DNS servers.
> +		push(@nameservers, $netsettings{'GREEN_ADDRESS'});
> +
> +		# Check if a BLUE zone exists.
> +		if ($netsettings{'BLUE_ADDRESS'}) {
> +			# Add the BLUE address to the array of nameservers.
> +			push(@nameservers, $netsettings{'BLUE_ADDRESS'});
> +		}
> +
> +		# Generate the line which will be written to the DNS servers file.
>  		$line = join(",", @nameservers);
>  	} else {
> +		# External net simply contains (any).
>  		$line = "\$EXTERNAL_NET";
>  	}
>  
>