Health Check feature in BIND ?

[Mike Hoskins (michoski)]

-----Original Message-----

From: Gaurav Kansal <gaurav.kansal at nic.in>
Date: Monday, June 17, 2013 3:27 AM
To: "bind-users at lists.isc.org" <bind-users at lists.isc.org>
Subject: Health Check feature in BIND ?

>Dear All,
> 
>I was just thinking whether it is possible to have a some type of health
>checking of servers through BIND DNS Server and DNS Server should replied
>to clients based on that only.
> 
>i.e., Suppose I have two entries of www record for domain
>xyz.in having ip address 10.1.1.10 and 10.2.2.10.
>Now I want that my DNS Server should check whether the server is up or
>not before replying to clients.
>If one is down, then DNS server should reply the IP address of the second
>one.
> 
>Although this is not a DNS Job and we should use Load-Balancer for this.
>But I just wanna to check whether this feature is available in Bind or in
>any Open-Source Program which in turn can be combined with BIND to
>achieve the desired result.

You are right, this is not the job of DNS alone...  A load balancer or
GSLB would be ideal.

There have been threads on similar things in the past.  One I recall
involved DDNS and local glue.  Scripts doing pings, port checks, etc
combined with low TTLs and dynamic updates to "route" around potential
problems.

Such an approach can have pitfalls, but does have a place and is
relatively easy to implement.