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Hi
The other posts have dealt with the routing and
redundant connectivity, but since no one has really address the servers... Even
the best hardware with the most stable OS will go down, so if you really need
maximum up time you need more than one server. You might want to look at a local
director (LD) which will also solve your DNS problem, as the LD will present a
single IP for both servers.
The idea of placing a LD in front of the www
servers, also presents a problem, another single point of failure. So it's goes
back to something I heard once, "the closer you get to 100% up time, the cost
will grow exponentially until you are busted." So unless you have some major
bucks 100% up time is a impossible dream.
HTH
--
John Hardman, CCNP
MCSE+I
Hi,
I need a solution for the configuration
below:
Internet
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ISP
A ISP B
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Customer
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---------------------------- Web Server
Web Server will has 2 IP addresses, one will be
given by ISP A and the other one will be given by ISP B.
Primary DNS server is on ISP A and
secondary DNS server is on ISP B.
The DNS server on ISP A has two records for
customer's web server, for example :
www a 10.0.0.1 (IP
address given by ISP A)
www a 20.0.0.1 (IP
address given by ISP B)
The goal is to use dual ISP for back-up purpose,
so the web server will serve for 24 hour / day.
Since the DNS server only load balance between
two same host records, how about if one link is broken ?
For example :
Link from ISP B to Customer is
broken, meanwhile someone in Internet is accessing the web server
and the DNS server give him the IP address of 20.0.0.1, so the
session will time out. He will has an access to web server until the
DNS server give him the IP address of 10.0.0.1 (because the DNS server
load balance these two records).
Are there any solutions to solve this
problem, so the DNS server could detect the unreachable IP address
and after that it would give the correct reachable IP
address to the client ?
Thank you
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