DNS failover
Hi all,
Can someone advice please if it's possible to monitor a VPN line from GTM, and respond to a DNS query based on the line status?
For example client uses 2 VPN lines (primary to DC1 and secondary to DC2) and has a zone forwarder for a domain hosted on my GTMs. Unfortunately it is not easy to setup zone forwarder to use the primary DNS by default, and secondary only in case of a failure. The DNS server uses round-robin instead. Let's assume it is not possible to re-configure the DNS server to use a different load-balancing algorithm at all. If that's the case then I have 2 choices:
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Currently I have setup DC1 and DC2 in the way where all members of all pools have the same order. This will ensure that even if the client's server sends request to DC2, GTM will respond with IP address of the DC1. Business requirement is met, but this is not good solution in case of the primary VPN goes down.
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Monitor DC1 line and response with a DC2 IP (from DC2 GTM) if the primary line is down.
Does anyone have similar problem? Is it possible to control this by an iRule?
Regards Mariusz