Domain name based multihome routing?

Matus UHLAR - fantomas uhlar at
Wed Jun 27 14:16:16 UTC 2018

>On Tue, Jun 26, 2018 at 12:45 PM, Grant Taylor via bind-users <
>bind-users at> wrote:
>> Are you saying that you want to dynamically update routes to IPs resolved
>> in real time to specific host / domain names?  Such that traffic to
>> specific hosts / domain names is routed over DSL?  With things that don't
>> match conditions routed over cell?

>I think I understand what you want to do and why you want to do it.

>> It seems like you're using named as the source of information to feed into
>> the process that dynamically updates routing.
>> I find the pausing of named to be questionable.  But I understand that you
>> want to make sure that no connections are started until after the
>> (re)routing has been done.

On 26.06.18 14:07, Dale Mahalko wrote:
>(I am no programming expert as mentioned, but I do IT stuff for a living,
>The pause would only be long enough to look for a regex domain pattern to
>be routed to the DSL, and then creating the route. This pause can likely be
>measured in nanoseconds.

I don't think this could be done in nanoseconds. Maybe microseconds, but
more probably miliseconds.

Another question would be, how fast your router can be with potentially
thousands of routes (I know, many OSes have routing optimised very hardly).

>This would likely be a multithreaded asynchronous mechanism so that BIND
>does each of its lookups as usual, and then forks a followup thread after
>it completes its normal lookup process, to do the pattern match and route
>creation, followed by the delayed response released when the
>pattern-match/route-creation thread terminates.
>So in general using multithreading, there would be no real impact to
>programs requesting the lookups, other than a delay per lookup that is so
>small it would not be noticeable to an end-user human.

I think that you are trying wrong approach, using wrong tools.
Guessing the potential usage from DNS is not a goog idea.

On your router, configure firewall to route selected protocols (gaming, ssh,
RDP, dns) and maybe later some sites to paid cellular and router everything
other to DSL.

Note that at my home, most of data is spend by my children watching youtube
videos - I don't think that routing general web and streaming services to
cell connection would help you with anything.

Matus UHLAR - fantomas, uhlar at ;
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