#! perl -w
my @domains = qw(foo.com weirdext.za bar.uk.com blah.co.uk perl.pl zzzz.co.uk);

my @sorted = map{ join '.',  reverse split( /\|/,$_ ) }
              sort 
              map {join '|', reverse split( /\./,$_,2) }  @domains;

{ local $"="\n"; print "@sorted"; }
__END__
# Output
C:\test>193114
blah.co.uk
zzzz.co.uk
foo.com
perl.pl
bar.uk.com
weirdext.za
C:\test>