Filter A records in an IPv6 only environment

Wed May 2 01:23:55 UTC 2018

Yes, unfortunately, I don't have control over the app(NPM) in NodeJS that
is making the call. A bit of a chicken and the egg problem since they
didn't make it the default...

On Tue, May 1, 2018 at 7:21 PM, Mark Andrews <marka at isc.org> wrote:

> Upgrading nodejs and getting verbatim=1 added to the appropriate call
> should also help.  The bug report you linked to showed that getaddrinfo
> result order will now be honoured with verbatim=1.  You then just need
> to ensure that getaddrinfo is correctly configured to return IPv6
> addresses before IPv4 addresses.  This should be the default for
> getaddrinfo.
>
> Mark
>
> > On 2 May 2018, at 10:50 am, Kim Ebert <kim at developmint.work> wrote:
> >
> > Yeah, fighting with the application developers doesn't appear to be a
> good option, nor is applying any tunneling mechanisms such as 464xlat.
> >
> > One of the main goals is to establish an ipv6 only network that just
> works. An ipv6 only network doesn't need A records. I'll give a link to my
> patch or repo when it is ready.
> >
> > Thanks for the feedback though. I appreciate it.
> >
> > As far as the application developer, it is nearly as frustrating as
> Android dhcpv6 support.
> >
> > Kim
> >
> > On Tue, May 1, 2018, 6:30 PM Mark Andrews <marka at isc.org> wrote:
> > Which is really because they don’t understand that happy eyeballs is
> > just a tweak to RFC 1123 multi-homed server support.  It isn’t IPv6
> > transition support. It’s just the IPv6 results in a LOT MORE MULTI-HOMED
> > sites especially when DNS64 is in the mix.
> >
> > Failure to honour address preferences returned from getaddrinfo should
> > be a firing squad offence.  Application developers DO NOT KNOW how the
> > network the application is connected to is configured.
> >
> > You could move to using DS-Lite, MAP-E, MAP-T, 464XLAT etc. to provide
> > IPv4 as a service instead of DNS64 + NAT64 (I presume you actually meant
> > DNS64 + NAT64 when you said NAT64).  Your local network can still be
> > IPv6-only.  MAP-T and 464XLAT can still use your NAT64 box.
> >
> > DS-Lite and MAP-E are different ways to automatically configure
> > IPv4 in IPv6 tunnels.
> >
> > MAP-T and 464XLAT are just different ways to configure the CLAT
> > which translates IPv4 packets to IPv6 packets before sending them
> > to the NAT64 for reverse translation.
> >
> > nodejs should work fine with all of DS-Lite, MAP-E, MAP-T and 464XLAT
> > as they allow A records (IPv4 literals) to work for connections.
> >
> > Mark
> >
> > > On 2 May 2018, at 9:47 am, Kim Ebert <kim at developmint.work> wrote:
> > >
> > > Developer had refused to apply happy eyeballs.
> > >
> > > See https://github.com/nodejs/node/issues/6307
> > >
> > > I can't fix the application, so I need to fix my network.
> > >
> > > Kim
> > >
> > > On Tue, May 1, 2018, 5:44 PM Mark Andrews <marka at isc.org> wrote:
> > > If you have a IPv6 only network then there should be no default IPv4
> route so
> > > the connect(), sendto() etc. should all fail immediately with network
> unreachable.
> > > If they don’t then complain to your OS developer. If the application
> does not
> > > detect these failures complain to the application developer.
> > >
> > > Applications should fail over immediately if there is not a covering
> route.
> > >
> > > If you have a local default IPv4 route, the router should be returning
> network
> > > unreachable and the OS should be processing them. This should cause
> network
> > > errors to be delivered to the application.
> > >
> > > The application should also be implementing happy eyeballs where you
> fail
> > > over to other addresses with sub second delays when there are multiple
> > > addresses to try.  There is nothing wrong with having multiple
> connection
> > > attempts happening in parallel.
> > >
> > > Mucking with DNS responses is only covering up application defects.
> Filtering
> > > A records also breaks DNS64 for applications that are using DNSSEC as
> they
> > > need to see the A records as well as the AAAA responses.
> > >
> > > Notify the application vendor they they have a denial-of-service bug.
> > >
> > > Mark
> > >
> > > > On 2 May 2018, at 9:00 am, Kim Ebert <kim at developmint.work> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I recently came across an issue where the user program preferred
> IPv4 over IPv6. This is a problem because I've created a network that is
> IPv6 only. I'm currently using NAT64 to provide access to services that
> don't have any IPv6 access.
> > > >
> > > > Now this particular program could work if the DNS records didn't
> provide A records. I would rather do everything I can as an admin to make
> the network just work instead of waiting for all of the end user programs
> to be fixed, so I started working on filter-a functionality to filter out A
> responses. Currently implementation status is that it sort of works, which
> is further than I expected to get in 2 days.
> > > >
> > > > I wonder if anyone in the community is interested in me sharing the
> work, and if I should go to the effort to publish the effort?
> > > >
> > > > If anyone is curious, the offending program is nodejs and npm.
> > > >
> > > > Thanks,
> > > >
> > > > Kim
> > > > _______________________________________________
> > > > Please visit https://lists.isc.org/mailman/listinfo/bind-users to
> unsubscribe from this list
> > > >
> > > > bind-users mailing list
> > > > bind-users at lists.isc.org
> > > > https://lists.isc.org/mailman/listinfo/bind-users
> > >
> > > --
> > > Mark Andrews, ISC
> > > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > > PHONE: +61 2 9871 4742              INTERNET: marka at isc.org
> > >
> > >
> > > On May 1, 2018 5:44 PM, "Mark Andrews" <marka at isc.org> wrote:
> > > If you have a IPv6 only network then there should be no default IPv4
> route so
> > > the connect(), sendto() etc. should all fail immediately with network
> unreachable.
> > > If they don’t then complain to your OS developer. If the application
> does not
> > > detect these failures complain to the application developer.
> > >
> > > Applications should fail over immediately if there is not a covering
> route.
> > >
> > > If you have a local default IPv4 route, the router should be returning
> network
> > > unreachable and the OS should be processing them. This should cause
> network
> > > errors to be delivered to the application.
> > >
> > > The application should also be implementing happy eyeballs where you
> fail
> > > over to other addresses with sub second delays when there are multiple
> > > addresses to try.  There is nothing wrong with having multiple
> connection
> > > attempts happening in parallel.
> > >
> > > Mucking with DNS responses is only covering up application defects.
> Filtering
> > > A records also breaks DNS64 for applications that are using DNSSEC as
> they
> > > need to see the A records as well as the AAAA responses.
> > >
> > > Notify the application vendor they they have a denial-of-service bug.
> > >
> > > Mark
> > >
> > >
> > > > On 2 May 2018, at 9:00 am, Kim Ebert <kim at developmint.work> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I recently came across an issue where the user program preferred
> IPv4 over IPv6. This is a problem because I've created a network that is
> IPv6 only. I'm currently using NAT64 to provide access to services that
> don't have any IPv6 access.
> > > >
> > > > Now this particular program could work if the DNS records didn't
> provide A records. I would rather do everything I can as an admin to make
> the network just work instead of waiting for all of the end user programs
> to be fixed, so I started working on filter-a functionality to filter out A
> responses. Currently implementation status is that it sort of works, which
> is further than I expected to get in 2 days.
> > > >
> > > > I wonder if anyone in the community is interested in me sharing the
> work, and if I should go to the effort to publish the effort?
> > > >
> > > > If anyone is curious, the offending program is nodejs and npm.
> > > >
> > > > Thanks,
> > > >
> > > > Kim
> > > > _______________________________________________
> > > > Please visit https://lists.isc.org/mailman/listinfo/bind-users to
> unsubscribe from this list
> > > >
> > > > bind-users mailing list
> > > > bind-users at lists.isc.org
> > > > https://lists.isc.org/mailman/listinfo/bind-users
> > >
> > >
> > > --
> > > Mark Andrews, ISC
> > > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > > PHONE: +61 2 9871 4742              INTERNET: marka at isc.org
> > >
> > >
> >
> > --
> > Mark Andrews, ISC
> > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > PHONE: +61 2 9871 4742              INTERNET: marka at isc.org
> >
>
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742              INTERNET: marka at isc.org
>
>
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