Optional DNS-Check or Ping-test for the Android App

[Fabian Schwamborn]

Am 16.01.2019 um 23:06 schrieb David Cowden:
>
>
> On Wed, Jan 16, 2019 at 1:29 PM Fabian Schwamborn 
> <fabian at familie-schwamborn.com <mailto:fabian at familie-schwamborn.com>> 
> wrote:
>
>     I think you misunderstood me. Most broadband providers don't offer
>     fixed IPv4. Due to privacy considerations, even under IPv6 on
>     normal connections, addresses will always change. (prefix) As soon
>     as an address changes and my dynamic DNS system registers it, an
>     IPsec or OpenVPN client on my phone can reconnect. (This happens
>     once a week).
>     The Wireguard app simply lacks a monitor to see if the IP address
>     has changed. Therefore a ttl in the DNS was introduced .... (After
>     a registered loss of the connection - also shown in the log - no
>     DNS request is executed and the tunnel breaks down permanently.)
>
>     I think the
>
> Yes, I thought you were asking for what you already have setup. My 
> apologies.
>
>     se are the most common scenarios with OpenWRT routers ...
>
>     Having a DNS entry does not mean that it always points to a static
>     ip, so when a tunnel disconnects, the Android-app itself
>     (userspace) should handle this like many other existing
>     VPN-Clients do by a re-query of the DNS entry...
>
>     My question is, is there any opinion on such an implementation?
>     Should i try to implement it into the android app and provide the
>     code? (Unfortunately i am not a good android app-developer)
>
> This sounds like something the wg-go userspace should support, not the 
> android or ios app ui.

The wg-go userspace application is just the interface to the kernel 
module (or an userspace program, that emulates the kernel module)

The Linux-Kernel is not able to resolve any DNS because it could only 
handle IP-Adresses. I don't think that it would be a good idea to write 
a dns-resolver for a kernel module.

 From my point of view, each connected endpoint has to be monitored 
periodically by a userspace program (in this case java or an additional 
go-module). In case of a tunnel malfunktion OR based on a timer the 
Hostname has to be re-resolved.

Therefore my current question: Are custom code contributions welcome in 
this respect?

I am currently thinking about adding a timer-supported tunnel monitoring 
to the app.


>
>     Am 16.01.2019 um 21:57 schrieb David Cowden:
>>     You need to setup dns for your home site then use that to
>>     connect. Or you need to synchronize the endpoint out of band. I
>>     can't imagine this is something wg wants to tackle--this is a
>>     general problem all software encounters.
>>
>>     On Tue, Jan 15, 2019 at 10:52 PM Fabian Schwamborn
>>     <fabian at familie-schwamborn.com
>>     <mailto:fabian at familie-schwamborn.com>> wrote:
>>
>>         Hello,
>>
>>         I have a suggestion for improving the Android app or would
>>         like to ask if such a change would be desirable in general
>>         (e.g. pull request):
>>
>>         I'm using Wireguard as a connection between my home router
>>         and my mobile phone, but unfortunately I don't have a fixed
>>         IP address. As soon as the IP address changes, the app does
>>         not reconnect. (Happens once a week)
>>
>>         Is it possible to integrate a function into the app, that
>>         pings through the tunnel so that you can perform a keep-alive
>>         check and reconnect the tunnel completely after a failure
>>         (including DNS request)?
>>
>>         Is it conceivable, to implement a DNS-check function in the
>>         app? (E.g. like the existing example DNS check script for
>>         Linux works?)
>>
>>         Then the app would have the same functionality as my previous
>>         IP-Sec client. This would also allow better coverage of
>>         failover IP scenarios.
>>
>>
>>         Best Regards
>>
>>         Fabian
>>
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>>
>
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