lo there all,
we are running a server at work that we are hosting several websites ( about 6 ) with name based virtual hosting in apache.

every once in a while our isp dies. Then we are out of buisness for a few hours until they fix whatever it was that crashed. Meanwhile, we need another isp to serve on. So, here are my questions. We are using zoneedit as a dns server.

So my questions are these:
how would i go about adding another ip address for each of the name based virtual hosts on our server?

can a domain name be resolved to two different ip addresses ? ( or, since we are going to be paying for the isp even when we don't need it, can we make use of the extra bandwidth to serve with ?)

can a seemless solution be had, or if we drop one isp, can we continue to serve up web pages without having to change things in the dns server or apache http.conf file?

any tips would be great, or links for good set up how-tos.
thansk

name based virtual hosting doesn't care what IP address you listen on unless you explicitly make that the case, indeed the apache server doesn't have any idea what the external IP address that was resolved even was, assuming that this server is not directly internet facing (please please say you've a firewall or something infront of it..)

A dns name can resolve to multiple IP's but that won't provide you with resilience, as once one person has resolved it to the wrong IP, it's never going to connect, and not go back to DNS again.

i'd say that you either need to manually update these DNS records via the registrar during a failure, or look to run your own DNS server where you can directly change records. DNS can take hours and hours to fully propagate though, so by the time you can guarentee the change is made, it may not be a problem any more.

ok, well, i guess i should have thought about the fact that apache does not know the external ip, we are behind a firewall/router, so our web server thinks it's at 10.10.10.9

So, if i use bind, or somesuch DNS server locally, and we loose our primary ISP, we are still basically down until we make the changes propagate through DNS ? rats..

So, really, what do you reckon would still be the best solution for this? The way it sounds, i would only want the backup isp to be pointed at our server if we went down ( since the bandwidth from that isp would be less than half of what we get from our main ISP ). Is this right?

thanks for your help.

i would suggest either getting a better ISP, or pay for proper hosting with 99.999% availability SLA's