- dns-wg - mailman.ripe.net

Re: [dns-wg] Fwd: [enum-wg] Tier-2 provisioning: NS vs CNAME/DNAME
by Jim Reid 15 Jul '04

15 Jul '04

>>>>> "Niall" == Niall O'Reilly <Niall.oReilly(a)ucd.ie> writes: >> I'm about to become responsible for a Tier-2 ENUM registry, >> part of the Irish ENUM Trial. I expect to use BIND as the name >> server platform for this purpose. I have supposed (perhaps >> naïvely) that the conventional delegation mechanism, using NS >> records in the parent zone, would be appropriate. This >> involves creating a new zone as each new telephone number is >> registered, and configuring the zone specifically on each of >> Tier-2 name servers. >> >> I'm not sure I really want to buy in to this level of >> per-number provisioning activity, and see apparently >> significant advantages in using the technique of RFC2317 >> (Classless IN-ADDR.ARPA delegation) to make life simpler. Actually I think it will make life harder. 2317-style delegation is trickier to set up and maintain than conventional delegation. >> The advantages I see are the following. >> >> The Tier-1 zone file becomes smaller, with just one CNAME (or >> DNAME) record per delegation, rather than two or more NS >> records. So what? Is disk space and RAM expensive? The T1 registry is going to be storing so much data about its registrations -- tech & admin contact details, billing info, authentication/validation tokens, whois tags, registrar data, etc, etc -- that shaving off a couple of resource records would be lost in the noise. For the T1, adding CNAMEs instead of conventional delegations might well be an unwanted complication: ie it requires changes and on-going support to the registry database and back-end scripts and tools. IIUC some registry systems only handle the RRs needed for conventional delegation: NS records and related glue. >> At Tier 2, the named configuration file needs only per-server, >> rather than per-number- per-server provisioning activity, and >> propagation of newly-registered numbers is driven by NOTIFY >> rather than by reloading the updated configuration file on each >> server. You lose the granularity of control and the flexibility to let customers manage their delegations. I'm presuming you plan to have all your numbers CNAME'd into a single zone file rather than discrete zone files for each zone. This might also get you into trouble with the competition authorities because the people using these CNAME'd numbers are locked in to your way of doing things. For something like a DDI block for an organisation, this shouldn't be an issue. But if it was for all numbers in the Dublin area code (say), there would be a problem. Registrants won't have the freedom to choose and switch DNS providers. Or decouple DNS hosting from the ISP/registrar they use to get their ENUM delegation. Using some sort of CNAME/DNAME trickery may limit your options for the future. ie It imposes a certain way of working or mindset that seems reasonable today. But it may not be the case in a year or so. And then all sorts of silliness happens as the original CNAME/DNAME model gets perverted to support the then prevailing orthodoxy. How often have we met bizarre DNS setups that have been inherited from an earlier DNS administrator who kludged a configuration and then kept tweaking it instead of doing the job properly? >> This looks like the way to go, but perhaps I'm missing >> something ? Using CNAME trickery for ENUM is unwise. It opens the door to all sorts of evils, like the accommodation of alternate trees. And it will make DNSSEC deployment (hah!) much harder because the parent can't secure any delegations with DS records because there are no proper delegations. DNAME is even worse because there are plenty of name servers and resolvers out there that don't understand this RR. It's not impossible that some applications will get upset if they get CNAME-like referrals to their lookups when they only expected to get NAPTR RRs or conventional referrals. For instance think of someone who writes a minimal ENUM-aware resolver as a Java applet for their mobile phone. Another problem -- which won't apply to someone clueful like you -- is that the introduction of CNAMEs increases the likelihood of looping or very long CNAME chains. Or dangling CNAMEs that point at nothing. Even without these administrative errors, the introduction of CNAMEs will complicate ENUM lookups and could mean they take too long. This would be somewhat annoying when someone picks up their ENUM-aware phone, dials a number and then waits for an eternity while the resolver chases down umpteen CNAME chains before making a phone ring. IMO it's best not to give people access to that much rope to hang themselves.

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Re: [dns-wg] Last Warning: Termination of <auto-inaddr@ripe.net>
by Jim Reid 14 Jul '04

14 Jul '04

>>>>> "Olaf" == Olaf M Kolkman <olaf(a)ripe.net> writes: Olaf> As announced previously (e.g. [1]), we will discontinue the Olaf> use of the <auto-inaddr(a)ripe.net> e-mail interface for Olaf> reverse delegation requests as of tomorrow (July 15, 2004). Olaf> From tomorrow, all mails sent to this address will be Olaf> returned to sender. I hope the bounce message tells the sender what email address they should have used or points them at a web page that gives this info.

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Last Warning: Termination of <auto-inaddr@ripe.net>
by Olaf M. Kolkman 14 Jul '04

14 Jul '04

Dear Colleagues, [Apologies for the duplicate messages] As announced previously (e.g. [1]), we will discontinue the use of the <auto-inaddr(a)ripe.net> e-mail interface for reverse delegation requests as of tomorrow (July 15, 2004). From tomorrow, all mails sent to this address will be returned to sender. Reverse delegation requests can only be submitted to the RIPE Whois Database by using the <auto-dbm(a)ripe.net> e-mail interface or by using one of the other update mechanisms such as web-updates[2]. For more information about the authentication mechanism, please see http://www.ripe.net/reverse -- Olaf Kolkman New Projects, RIPE NCC [1] http://www.ripe.net/ripe/mail-archives/dns-wg/2004/msg00042.html [2] Webupdates interface to the RIPE Whois Database. http://www.ripe.net/perl/webupdates.pl If you are reading this or related posts from the archive all occurrences of ripe.net in e-mail addresses have been replaced by localhost -- ---------------------------------| Olaf M. Kolkman ---------------------------------| RIPE NCC

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Re: [dns-wg] Re: FYI: IANA delegation procedure for the root zone and ipv6 glue
by geoff＠nominet.org.uk 13 Jul '04

13 Jul '04

Stephane Bortzmeyer <bortzmeyer(a)nic.fr> writes: > On Tue, Jul 13, 2004 at 10:51:55AM +0200, > Jeroen Valcke <jeroen.valcke(a)belnet.be> wrote > a message of 18 lines which said: > > > Now, I was wondering whether IPv6 glue records have already been > > added in the root zone. To my knowledge not, is that correct? > > Correct. ftp://rs.internic.net/domain/root.zone.gz > > > Are there TLDs who already submitted IPv6 glue records? > > We did, on 17th February 2003. At the CENTR GA Meeting last month, Doug Barton announced that AAAA RRs would be introduced into the root zone by the end of June, but this has not yet happened. Regards Geoff

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Re: [dns-wg] Policy for Reverse DNS for End-User PA Addresses?
by Jim Reid 09 Jul '04

09 Jul '04

Jørgen, you raise an interesting question. This subject is certainly something for the WG to consider. How about presenting something at the next RIPE meeting? My personal opinion is that a mandatory policy is likely to be too cumbersome. It could also be painful for ISPs and the NCC: creating inetnum objects for every /29 or whatever an ISP gives to its DSL customers. That might also open the door to other complications. If some DSL user is in the NCC database because of an inetnum object for reverse delegation, maybe that user should be paying NCC fees? And does that user become responsible for maintaining that inetnum and related objects in the database? I've also got a gut feel that reverse delegation is really an issue between an ISP and its customer. If some ISP won't do reverse delegation properly (or at all), the customer is free to pick another ISP that does. Economic Darwinism should sort this out, just like it eliminates the clueless ISPs with lousy service. A document advising about reverse delegations which customers can put in front of their ISP would be no bad thing though. That said, I would welcome a discussion about the subject and encourage the WG, especially those at DSL providers, to speak up. I would also be pleased for the WG to produce some document on reverse delegation and strongly recommends this gets done properly. Making reverse delegation mandatory for all customer IP addresses may be a step too far IMO, but let the WG decide this. Perhaps you could start the ball rolling by preparing an initial draft with a view to starting a work item? I'm a great believer in delegation (excuse the pun), so over to you.... and the WG.

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Re: [dns-wg] Policy for Reverse DNS for End-User PA Addresses?
by Jim Reid 09 Jul '04

09 Jul '04

>>>>> "Brad" == Brad Knowles <brad.knowles(a)skynet.be> writes: Brad> But we're not talking about the general solution. Brad> We're talking about issues with DSL providers. So incorrect reverse delegation for customer IP addresses only happens with DSL providers, does it?

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Re: [dns-wg] Policy for Reverse DNS for End-User PA Addresses?
by Jim Reid 09 Jul '04

09 Jul '04

>>>>> "Brad" == Brad Knowles <brad.knowles(a)skynet.be> writes: >> Brad, please re-read what I said. I spoke about ISPs, not DSL >> providers. Brad> At least in some countries, the DSL provider owns the Brad> reverse DNS, not the ISP. To repeat myself: please re-read what I said. If bit-shifter A won't do reverse DNS to a customer's liking, the customer can go to bit-shifter B who does. How A and B shift bits is irrelevant: DSL, avian carriers, cable modems, whatever. It all comes down to a trade-off between cost, QoS, bandwidth and reverse DNS. If reverse DNS is the over-riding concern for someone, they can always find an ISP who will do this. Though it may be from an ISP that doesn't do DSL. >> If working reverse DNS is a very important consideration for >> some customer, they can always find an ISP who can accommodate >> that. Brad> Not all ISPs provide their own access. In Belgium, I Brad> believe that Belgacom is the only DSL access provider that Brad> is allowed by law. Everyone else has to resell DSL access Brad> from Belgacom, and Belgacom owns the reverse DNS. So what? If they won't do reverse DNS to your liking, try a cable company. Or get Level3 (say) to run fibre into your basement. Or do dialup over your GSM. There's always a solution. But it might not be as cheap or convenient as DSL from the incumbent. That's why I said people can always vote with their wallets. In the case of a monopoly provider, a "Correct Reverse DNS Is A Very Good Thing" document from the WG might be helpful if their policies are not addressing their customer's needs and those customers have nowhere else to go.

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Re: [dns-wg] Policy for Reverse DNS for End-User PA Addresses?
by Jim Reid 09 Jul '04

09 Jul '04

>>>>> "Brad" == Brad Knowles <brad.knowles(a)skynet.be> writes: >> I've also got a gut feel that reverse delegation is really an >> issue between an ISP and its customer. If some ISP won't do >> reverse delegation properly (or at all), the customer is free >> to pick another ISP that does. Economic Darwinism should sort >> this out, just like it eliminates the clueless ISPs with lousy >> service. Brad> I disagree. In many cases, there is one and only one Brad> DSL provider for a given address -- the old telephone Brad> monopoly continues to have a stranglehold here. Brad, please re-read what I said. I spoke about ISPs, not DSL providers. If working reverse DNS is a very important consideration for some customer, they can always find an ISP who can accommodate that. This might of course mean choosing some other way of shifting bits from what any monopoly DSL provider has to offer. So the customer makes their choice and pays their money. This probably is a much more effective way of getting results than writing up a BCP. Please note that I'm not saying monopoly DSL (or whatever) providers should be encouraged to ignore reverse DNS for their customers.

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Re: [dns-wg] Policy for Reverse DNS for End-User PA Addresses?
by Jim Reid 08 Jul '04

08 Jul '04

>>>>> "Peter" == Peter Koch <pk(a)TechFak.Uni-Bielefeld.DE> writes: Peter> Well, does the recipient of assigned address space now Peter> (directly) pay an NCC fee? Well I'm not even though my ISP gave me a /28. I suppose some percentage of my DSL bill goes towards my ISP's contributions to the NCC. >> about reverse delegations which customers can put in front of >> their ISP would be no bad thing though. Peter> What I've read between the lines is that in the case of DSL Peter> the classless delegation method may not be sufficient, even Peter> if the ISP is able and willing. Due to dynamic nature of Peter> address assignments they'd need something similar to dyndns Peter> (and friends) for the reverse mapping. So, is anyone doing Peter> this already? No idea. Anyone?

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Policy for Reverse DNS for End-User PA Addresses?
by Jørgen Elgaard Larsen 08 Jul '04

08 Jul '04

Hi there, I would like to share some thoughts on reverse DNS with you. In my experience, reverse DNS often works well with larger organisations that have been assigned a /24 IPv4 range or greater. On the other hand, it almost never works with smaller organisations using smaller ranges, e.g. on ADSL lines. As I see it, there is a general trend that more and more small and mid-size businesses uses ADSL lines for connectivity. Since IPv4 addresses are scarce, these businesses are often assigned IPv4 ranges smaller than /24 - many only get a /30 range. Nevertheless, they still operates servers for various purposes. The problem is that ISPs typically are very hesitant to administer reverse DNS for these addresses. Either these addresses have no reverse DNS at all, or they resolve to a semi-random host name (e.g. address aaa.bbb.ccc.ddd resolves to aaa.bbb.ccc.ddd.adsl.isp-name.com) If the ISP (or whoever administers reverse DNS for the /24 range) do not wish to help out, there is really nothing the end user can do. Apart from being _really_ annoying to the end user, it also undermines reverse DNS as such: It is already difficult to convince everybody to set up reverse DNS, but even if an end user wants to do it, it may not be possible for him. I am aware that it would take some work for RIPE NCC to force every ISP to properly administer reverse DNS, but there are several costless methods that would help a lot. Please consider these suggestions: a) Make it mandatory for ISPs to offer classless reverse delegation to end users with RIPE-assigned IP ranges (i.e. for PA IP ranges that has a inetnum object with an end user as admin-c). Even if this would not be actively enforced, it would be a great help to end users if they could point to an official RIPE policy on this. Even a web page saying that LIRs _should_ do so would be a help. b) Make it mandatory for ISPs to offer either classless delegation or reverse DNS at IP-level for all its assigned addresses. Again, if there are no ressources to enforce it, it would still help to make it official RIPE NCC policy. c) Extend the new reverse delegation system to include classless delegation of PA addresses. For this to work, it would probably be necessary to move master DNS for all split ranges to RIPE NCC, which of course would increase the load on RIPE NCC. Administration, on the other hand, could be fully automatised. There are probably many other ways, too. Anyhow, I would really like a solution to this. Sincerely, Jørgen E. Larsen CTO Elgaard Data jel(at)elgaard.net

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