use strict;
use warnings;

open my $inFH, q{<}, \ <<EOD or die qq{open: < \ HEREDOC: $!\n};
dnsname1:            static-route 1.1.1.1/30 next-hop 2.2.2.2 preference 200 bfd-enable tag 685
dnsname1-            service-name "XYZ12345-s12345"
dnsname2:            static-route 3.3.3.3/30 next-hop 4.4.4.4 bfd-enable tag 635
dnsname2-            service-name "XYZ67891-s67890"
EOD

my $data = do {
   local $/;
   <$inFH>;
   };

close $inFH or die qq{close: < \ HEREDOC: $!\n};

$data =~ s{\n\S+-}{}g;

open $inFH, q{<}, \ $data or die qq{open: < \ scalar: $!\n};

while (<$inFH>  )
{
    # Do a single data extraction regex here.
    ...
}

close $inFH or die qq{close: < \ scalar: $!\n};