Hi. Yet another DNS question:

If I register domain.com using the name servers dns1.hosting.com, dns2.hosting.com, dns3.hosting.com and dns4.hosting.com (all fictional) - assuming dns1 and dns2 are on seperate networks (not that it matters), if lets say dns1 goes down, will the internet use only dns2,3,4 and not 1? I think this is how the whole internet works with the 13 root servers right? BEcause if one goes down the internet stops querying them and uses the others right? Since there is a 24 hour ttl on the main internet domains, if lets say i visited domain.com at 2pm my isp will remember the name servers for 24 hours, so if a dns server is down will the isp just ignore it?

Thanks

Hi,

You are correct if dns1 dies forever dns2 will do the work of resolving domains to ip addresses.

It is good to have dns1 and dns2 on different C class ips to help prevent DOS attacks and if someone accidently removes you IP block from the router you will still have plenty of DNS servers running to keep your site up.

Hope this helps.

-Frank

what did that mean? - if dns1 dies forever, dns2 will work OR if dns1 dies, forever dns2 will do it?

So who does the checking? IE if i goto www.yahoo.com and yahoo.com returns 5 name servers, will my pc/isp check the name server if its up and if its not, then only use up ones or do the 13 root servers return only up name serverS?

As I remember the root servers only return a list of name servers, your computer then tries the first on the list, if no responce, then the second one responds, and so on...