I think you didn't mean domain. In that case, the catchall address encourages delivery. I'm looking for a guaranteed bounce, for test purposes, at any email service provider. If you did mean domain, domains like example.com would give a different result than sending to a real domain. The same address at any provider would be better. -- Nick _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf