Multiple DNS servers via static configuration?

Quick question…when manually configuring DNS servers using the IPAddress dns(192,168,1,1) syntax, I have the following questions:

  1. Can you list more than one DNS server?
  2. If you can list more than one, is it a round-robin selection or does it only try #2 after #1 times out?
  3. What is the timeout?
  4. How long are the results cached?


Can you list more than one DNS server?

No, only one.

What is the timeout?

5 seconds. (Yes, that seems short to me too. It’s not configurable.)

How long are the results cached?

There is no DNS cache; every time you do a TCPClient.connect by hostname or a name lookup a DNS query is done.

@rickkas7, thanks for the info.

Given the recent downtime that Particle experienced, perhaps somebody could take a look at this issue? In today’s world, being able to specify only one server for any function isn’t very conducive to the “ilities” that network engineers require. You should be able to configure a minimum of two and maybe even up to 4. Round-robin. Timeout should be configurable, and even a small cache would be appreciated.

And…as I always say…update the documentation with the information that @rickkas7 was kind enough to provide.

Are you routing your WiFI traffic through your own (single) router/AP?
If so, you have the single point of failure there already. On the other hand, when it comes to DNS usually your router/AP will have a set of alternative DNS addresses to choose from and hence once your Photon (I guess) can talk to that router it already has access to multiple DNSs.

I am routing through a single AP which I do control. And yes, that does represent a single point of failure, but I can control that by adding more AP’s if needed. And yes, my AP could be programmed with multiple DNS entries, but only because they do allow multiple DNS servers. In general, this is such a common configuration option that it should be added, regardless of what other workarounds could be configured.