Filter A records in an IPv6 only environment

Wed May 2 01:21:33 UTC 2018

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