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Dec 10, 2013 at 12:49 comment added user @Eiver Yes, that should be about it. You can include a different configuration file from your main configuration file; it should be possible to make that name a symlink to one or the other based on the current link status. Or you could just rewrite the file. If you have any further questions specifically about how to set this up on the BIND side, please post that as a separate question.
Dec 10, 2013 at 8:45 comment added Eiver I already have a split horizon DNS with 2 views, because I wanted to be authoritative for my own domain and I wanted it to be resolved on LAN to 192.168.0.1, rather than the public IP address. Zone "." is currently inside view LANView{}, with match-clients { 192.168.0.0/24; 127.0.0.0/8; }; Zone "." is currently set to type hint. If I change hint to master and define the zone correctly, that should do the trick. Correct?
Dec 9, 2013 at 21:56 history edited user CC BY-SA 3.0
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Dec 9, 2013 at 21:47 comment added user @Eiver Just use some known host on your ISP's network, like their DNS resolvers or the next hop gateway. Pick a reasonable interval and I doubt anyone will make a fuss. The appropriate interval depends mostly on how quickly you want to detect a link outage and take steps to mitigate the situation. By the time the link is down you can decrease the time between attempts in order to recover soon after the link comes back up, since it won't really have an impact on anyone else anyway. The most important thing is to make absolutely sure you don't leak a fake root zone onto the Internet.
Dec 9, 2013 at 21:21 comment added Eiver BGP is not an option, therefore - ping. Pinging every 5 mins a host taken randomly from a list of a dozen or so hosts shouldn't count as a DoS attack I hope. Redirecting with BIND is absolutely great idea as I already have BIND configured as a caching DNS. Bonus points for configuration examples.
Dec 9, 2013 at 21:10 vote accept Eiver
Dec 9, 2013 at 19:24 comment added user @goldilocks Well, I suspect something like BGP could in principle help, but it still won't be guaranteed and someone asking this question probably isn't in a position to be able to rely on BGP anyway. The best way then is to simply do something that is known to solicit a response from the other end of the link. For which ICMP echo requests are ideally suited.
Dec 9, 2013 at 16:16 comment added goldilocks +1 AFAIK it's impossible to say whether a connection can exist without a transmission, and that's pretty much what the ICMP ping is for. When a connection becomes impossible because of a failure somewhere in the middle, there's no magical feature of the networking stack that can alert you of this.
Dec 9, 2013 at 15:00 history answered user CC BY-SA 3.0