www.cygwin.com DNS setup

www.cygwin.com DNS setup

[Chad Kimes]

Hi all,

I'm investigating an issue with GitHub Actions runners having issues
connecting to www.cygwin.com:
https://github.com/actions/virtual-environments/issues/698

I worked with the Azure DNS team and in this comment
<https://github.com/actions/virtual-environments/issues/698#issuecomment-628284472>
I
detail what we believe to be the likely issue. Summarized:

www.cygwin.com is CNAME'd to server2.sourceware.org
server2.sourceware.org is an NS server for sourceware.org

We believe that the above configuration is triggering a bug in WinDNS that
is causing intermittent DNS resolution failures. I don't have an ETA for
resolution from the Azure DNS team, and internally I'm translating that to
be on the order of months before we see a fix. In order to resolve this
faster for customers, I'm reaching out to see what options we have for
updating the DNS records that are triggering this bug.

Is there a change you can make to either www.cygwin.com or
server2.sourceware.org DNS such that it doesn't have this recursive
reference issue? Some options are to replace the CNAME with an A record, or
to use something like ns2.sourceware.org for the NS record instead of
server2.sourceware.org which is being used for cygwin's A record reference.

Thanks,
-Chad

Re: www.cygwin.com DNS setup

[Jon Turney]

On 14/05/2020 16:54, Chad Kimes via Cygwin wrote:
> Hi all,
> 
> I'm investigating an issue with GitHub Actions runners having issues
> connecting to www.cygwin.com:
> https://github.com/actions/virtual-environments/issues/698
> 
> I worked with the Azure DNS team and in this comment
> <https://github.com/actions/virtual-environments/issues/698#issuecomment-628284472>
> I
> detail what we believe to be the likely issue. Summarized:
> 
> www.cygwin.com is CNAME'd to server2.sourceware.org
> server2.sourceware.org is an NS server for sourceware.org
> 
> We believe that the above configuration is triggering a bug in WinDNS that
> is causing intermittent DNS resolution failures. I don't have an ETA for
> resolution from the Azure DNS team, and internally I'm translating that to
> be on the order of months before we see a fix. In order to resolve this
> faster for customers, I'm reaching out to see what options we have for
> updating the DNS records that are triggering this bug.
> 
> Is there a change you can make to either www.cygwin.com or
> server2.sourceware.org DNS such that it doesn't have this recursive
> reference issue? Some options are to replace the CNAME with an A record, or
> to use something like ns2.sourceware.org for the NS record instead of
> server2.sourceware.org which is being used for cygwin's A record reference.

I have drawn the attention of sourceware overseers to this.

They have requested the DNS change you suggest.

Re: www.cygwin.com DNS setup

[Chad Kimes]

Thanks Jon!

I see the change went through and I re-ran my validation script a few times
and I don't see the error anymore, which is awesome.

However, I believe my suggestions have inadvertently broken IPv6
connectivity for www.cygwin.com! The CNAME accounts for both A and AAAA
records, but only an A record was added after the CNAME was removed.

To fix this, can you please suggest that the team add an AAAA record
pointing to 2620:52:3:1:0:246e:9693:128c (the address for
server2.sourceware.org)?

Thanks,
-Chad

On Thu, May 14, 2020 at 12:31 PM Jon Turney <jon.turney@dronecode.org.uk>
wrote:

> On 14/05/2020 16:54, Chad Kimes via Cygwin wrote:
> > Hi all,
> >
> > I'm investigating an issue with GitHub Actions runners having issues
> > connecting to www.cygwin.com:
> > https://github.com/actions/virtual-environments/issues/698
> >
> > I worked with the Azure DNS team and in this comment
> > <
> https://github.com/actions/virtual-environments/issues/698#issuecomment-628284472
> >
> > I
> > detail what we believe to be the likely issue. Summarized:
> >
> > www.cygwin.com is CNAME'd to server2.sourceware.org
> > server2.sourceware.org is an NS server for sourceware.org
> >
> > We believe that the above configuration is triggering a bug in WinDNS
> that
> > is causing intermittent DNS resolution failures. I don't have an ETA for
> > resolution from the Azure DNS team, and internally I'm translating that
> to
> > be on the order of months before we see a fix. In order to resolve this
> > faster for customers, I'm reaching out to see what options we have for
> > updating the DNS records that are triggering this bug.
> >
> > Is there a change you can make to either www.cygwin.com or
> > server2.sourceware.org DNS such that it doesn't have this recursive
> > reference issue? Some options are to replace the CNAME with an A record,
> or
> > to use something like ns2.sourceware.org for the NS record instead of
> > server2.sourceware.org which is being used for cygwin's A record
> reference.
>
> I have drawn the attention of sourceware overseers to this.
>
> They have requested the DNS change you suggest.
>

Re: www.cygwin.com DNS setup

[Chad Kimes]

Hi all - gentle ping here. I want to make sure Cygwin doesn't have any
issues with IPv6 connectivity after this change. Could you look into
suggesting the above AAAA record to the responsible team?

Thanks!
-Chad

On Fri, May 15, 2020 at 11:47 AM Chad Kimes <chkimes@github.com> wrote:

> Thanks Jon!
>
> I see the change went through and I re-ran my validation script a few
> times and I don't see the error anymore, which is awesome.
>
> However, I believe my suggestions have inadvertently broken IPv6
> connectivity for www.cygwin.com! The CNAME accounts for both A and AAAA
> records, but only an A record was added after the CNAME was removed.
>
> To fix this, can you please suggest that the team add an AAAA record
> pointing to 2620:52:3:1:0:246e:9693:128c (the address for
> server2.sourceware.org)?
>
> Thanks,
> -Chad
>
> On Thu, May 14, 2020 at 12:31 PM Jon Turney <jon.turney@dronecode.org.uk>
> wrote:
>
>> On 14/05/2020 16:54, Chad Kimes via Cygwin wrote:
>> > Hi all,
>> >
>> > I'm investigating an issue with GitHub Actions runners having issues
>> > connecting to www.cygwin.com:
>> > https://github.com/actions/virtual-environments/issues/698
>> >
>> > I worked with the Azure DNS team and in this comment
>> > <
>> https://github.com/actions/virtual-environments/issues/698#issuecomment-628284472
>> >
>> > I
>> > detail what we believe to be the likely issue. Summarized:
>> >
>> > www.cygwin.com is CNAME'd to server2.sourceware.org
>> > server2.sourceware.org is an NS server for sourceware.org
>> >
>> > We believe that the above configuration is triggering a bug in WinDNS
>> that
>> > is causing intermittent DNS resolution failures. I don't have an ETA for
>> > resolution from the Azure DNS team, and internally I'm translating that
>> to
>> > be on the order of months before we see a fix. In order to resolve this
>> > faster for customers, I'm reaching out to see what options we have for
>> > updating the DNS records that are triggering this bug.
>> >
>> > Is there a change you can make to either www.cygwin.com or
>> > server2.sourceware.org DNS such that it doesn't have this recursive
>> > reference issue? Some options are to replace the CNAME with an A
>> record, or
>> > to use something like ns2.sourceware.org for the NS record instead of
>> > server2.sourceware.org which is being used for cygwin's A record
>> reference.
>>
>> I have drawn the attention of sourceware overseers to this.
>>
>> They have requested the DNS change you suggest.
>>
>