I have a client that wanted their DNS servers hosted by Zerigo, which I happily setup last year for them. Early this morning, Zerigo was hit with a Denial Of Service attack which took down this clients email and web site. I quickly switched the DNS servers back to my DNS servers and the site and their email was restored. Question I have is, is there any way to automatically do this if it were to happen again. For instance, can I enter the Zerigo DNS entries at the registrar and then enter my DNS servers as well just as a back up to the Zerigo DNS servers. Is there anything I would need to do? Is this something I should not do? Just trying to help prevent more downtime for this client. Any help or advice would be greatly appreciated.
you can specify up to 4 (I think) nameservers for every domain name, so yes you can specify your backup dns as a secondary nameserver