We don't have the sysctl any more, resulting in this binding to v6 only.

Index: lib/Net/Server/Proto.pm
--- lib/Net/Server/Proto.pm.orig
+++ lib/Net/Server/Proto.pm
@@ -163,10 +163,7 @@ sub get_addr_info {
 }
 
 sub _bindv6only {
-    my $class = shift;
-    my $val = $class->_sysctl('net.ipv6.bindv6only'); # linux
-    $val = $class->_sysctl('net.inet6.ip6.v6only') if ! length($val); # bsd
-    return $val;
+    return '1'; # OpenBSD requires separate binds for v4 and v6.
 }
 
 sub _sysctl {