We're seeing a huge uptick in reverse dns lookup failures across an app,
99% are all for Cloudflare ip addresses.
Instead of seeing a PTR or NXDOMAIN we're getting back SERVFAIL.
Does anyone know if this is a standard response from them? Do they not have
reverse DNS setup for their networks?
Trying to narrow this down to see if it's a result in a change in how our
application handles these errors or if there's an issue going on with
cloudflare's DNS setup.
Thanks!
Jeremy
We're seeing a huge uptick in reverse dns lookup failures across an app,
99% are all for Cloudflare ip addresses.Instead of seeing a PTR or NXDOMAIN we're getting back SERVFAIL.
Does anyone know if this is a standard response from them? Do they not have
reverse DNS setup for their networks?
Got an example range? All the ones I'm checking here seem fine.
If you are delegated a zone then you should answer queries for that
zone. SERVFAIL is not appropriate. It indicates a condition that
needs to be fixed especially from a authoritative server. Contact
Cloudflare with a list of failing names. Cloudflare are generally
good about making sure the DNS is giving well formed answers.
The following is general and is not directed at Cloudflare. I know
some people don't think errors in the reverse DNS are not critical
but if you are delegated a zone it is your responsablity to ensure
your servers are correctly serving that zone regardless of where
it is in the DNS heirarchy. Failure to do that causes additional
work for recursive servers. If you don't want to serve a zone then
remove the delegation.
Mark
Once upon a time, Mark Andrews <marka@isc.org> said:
The following is general and is not directed at Cloudflare. I know
some people don't think errors in the reverse DNS are not critical
but if you are delegated a zone it is your responsablity to ensure
your servers are correctly serving that zone regardless of where
it is in the DNS heirarchy. Failure to do that causes additional
work for recursive servers. If you don't want to serve a zone then
remove the delegation.
You are assuming that an authoritative server operator has some way to
know all the zones people delegate to their servers, and remove such
delegations if they don't want to handle them. That is a wrong
assumption.
Even more generally is that your authoritative server should respond to anything it is asked with an appropriate answer. Dropping/filtering can lead to bad situations.
Once upon a time, Mark Andrews <marka@isc.org> said:
> The following is general and is not directed at Cloudflare. I know
> some people don't think errors in the reverse DNS are not critical
> but if you are delegated a zone it is your responsablity to ensure
> your servers are correctly serving that zone regardless of where
> it is in the DNS heirarchy. Failure to do that causes additional
> work for recursive servers. If you don't want to serve a zone then
> remove the delegation.You are assuming that an authoritative server operator has some way to
know all the zones people delegate to their servers, and remove such
delegations if they don't want to handle them. That is a wrong
assumption.
They have methods. They choose not to use them. See RFC 1033
COMPLAINTS then after that the court system.
Mark
Once upon a time, Mark Andrews <marka@isc.org> said:
The following is general and is not directed at Cloudflare. I know
some people don't think errors in the reverse DNS are not critical
but if you are delegated a zone it is your responsablity to ensure
your servers are correctly serving that zone regardless of where
it is in the DNS heirarchy. Failure to do that causes additional
work for recursive servers. If you don't want to serve a zone then
remove the delegation.You are assuming that an authoritative server operator has some way to
know all the zones people delegate to their servers, and remove such
delegations if they don't want to handle them. That is a wrong
assumption.They have methods. They choose not to use them. See RFC 1033
COMPLAINTS then after that the court system.Mark
Let us review this and compare to your statement…
From RFC 1033:
COMPLAINTS
These are the suggested steps you should take if you are having
problems that you believe are caused by someone else's name server:1. Complain privately to the responsible person for the domain. You
can find their mailing address in the SOA record for the domain.2. Complain publicly to the responsible person for the domain.
3. Ask the NIC for the administrative person responsible for the
domain. Complain. You can also find domain contacts on the NIC in
the file NETINFO:DOMAIN-CONTACTS.TXT4. Complain to the parent domain authorities.
5. Ask the parent authorities to excommunicate the domain.
1. Doesn’t really apply in a situation where someone has pointed
an NS record for a domain at your server without warning. There
is no SOA record from which to retrieve said mailing address.
Also doesn’t work very well in cases where the SOA record does
not contain a valid email address that reaches someone.
2. Do we really want NANOG buried in “Will the
@#@!@$!@$% who delegated XYZ.COM <.xyz Domain Names | Join Generation XYZ; NS Records to point to
my servers <name> and <name> please cease and desist?”
messages? Personally, I vote no.
3. The NIC? Please explicate Mr. Andrews what that would mean
in the modern era. Please cover both the normal case and
the cases where domain privacy is configured.
4. This might _MIGHT_ actually work, but I suspect that $REGISTRY
is unlikely to help much when $REGISTRAR accepted an NS record
from one of their customers for a domain they registered
that happens to point to your server. Similarly, I suspect
$REGISTRAR is going to tell you that they won’t make changes
without authorization from the domain owner.
5. I suspect that success in this effort will likely parallel
the level of success I would expect in step 4.
So, now that we’ve realized that RFC-1033 is utterly useless in this
context and badly outdated to boot, let’s review your other suggestion…
“… after that [sic] the court system.”
[sic] refers to the missing comma.
So let me see if I understand correctly.
I run a pair of nameservers. Let’s call them ns1.company.com <http://ns1.company.com/> and ns2.company.com <http://ns2.company.com/>
Someone registers example.com <http://example.com/> and points NS records in the COM zone at my
nameservers.
I’m now supposed to seek judicial relief in order to compel them to stop
doing that?
Small claims doesn’t process claims seeking injunctive relief. I suppose I could
use a $1,500 or even $5,000 small claims case as a way to get their attention,
but that’s kind of an abuse of the process. If I want an injunction, at least
in California, I have to go to Superior court.
Now, first, we have to figure out jursidiction. As a general rule, jurisdiction
goes to the court which is responsible for the locale in which the event takes
place or where the contract was entered into, or the jursidiction set by the
contract. In this case, there’s no contract, so we have to look at where the
event in question occurred. The problem is that the law hasn’t really caught
up with technology in this area and depending on who ends up being parties
to the suit, the definition gets pretty murky at best. Is it the primary
office of the registry? The registrar? The registrant? The location of the
nameserver(s) which are erroneously pointed to? (What if they are anycast
all over the world?) The business address of the operator or owner of those
nameservers? Where, exactly do we file this suit?
The next problem we have is who to sue. Do we sue the domain registrant? The
registrar they used to register the domain name? etc.
Yeah, I don’t think there’s enough possibility of any sort of recovery to
make that worth the effort or expense.
Owen
>
>
>> Once upon a time, Mark Andrews <marka@isc.org> said:
>>> The following is general and is not directed at Cloudflare. I know
>>> some people don't think errors in the reverse DNS are not critical
>>> but if you are delegated a zone it is your responsablity to ensure
>>> your servers are correctly serving that zone regardless of where
>>> it is in the DNS heirarchy. Failure to do that causes additional
>>> work for recursive servers. If you don't want to serve a zone then
>>> remove the delegation.
>>
>> You are assuming that an authoritative server operator has some way to
>> know all the zones people delegate to their servers, and remove such
>> delegations if they don't want to handle them. That is a wrong
>> assumption.
>
> They have methods. They choose not to use them. See RFC 1033
> COMPLAINTS then after that the court system.
>
> MarkLet us review this and compare to your statement…
From RFC 1033:
> COMPLAINTS
>
> These are the suggested steps you should take if you are having
> problems that you believe are caused by someone else's name server:
>
>
> 1. Complain privately to the responsible person for the domain. You
> can find their mailing address in the SOA record for the domain.
>
> 2. Complain publicly to the responsible person for the domain.
>
> 3. Ask the NIC for the administrative person responsible for the
> domain. Complain. You can also find domain contacts on the NIC in
> the file NETINFO:DOMAIN-CONTACTS.TXT
>
> 4. Complain to the parent domain authorities.
>
> 5. Ask the parent authorities to excommunicate the domain.1. Doesn’t really apply in a situation where someone has pointed
an NS record for a domain at your server without warning. There
is no SOA record from which to retrieve said mailing address.
If they have pointed a NS record at you there is a SOA record. Either
in the zone or in the delegating zone.
Also doesn’t work very well in cases where the SOA record does
not contain a valid email address that reaches someone.
Some do, some don't. There is also whois address, web contact addresses
etc.
2. Do we really want NANOG buried in “Will the
@#@!@$!@$% who delegated XYZ.COM <.xyz Domain Names | Join Generation XYZ; NS Records to
point to
my servers <name> and <name> please cease and desist?”
messages? Personally, I vote no.
Why not. It is a operational message about a misconfiguration.
3. The NIC? Please explicate Mr. Andrews what that would mean
in the modern era. Please cover both the normal case and
the cases where domain privacy is configured.4. This might _MIGHT_ actually work, but I suspect that $REGISTRY
is unlikely to help much when $REGISTRAR accepted an NS record
from one of their customers for a domain they registered
that happens to point to your server. Similarly, I suspect
$REGISTRAR is going to tell you that they won’t make changes
without authorization from the domain owner.
The registrar becomes party to the disruption to your services and
no the contract the registry signed with ICANN does not save them
from being fined by a court further down the process so they should
listen as it is their finanical interests to listen.
Criminal law trumps contract law and deliberate disruption to
services falls under criminal law. It becomes deliberate once they
fail to act on the complaint in a timely manner. Remember we are
dealing with matters of fact here. Published NS records and address
records.
Add to that there are published proceedures that are not being
followed that they should be aware of.
5. I suspect that success in this effort will likely parallel
the level of success I would expect in step 4.So, now that we’ve realized that RFC-1033 is utterly useless in this
context and badly outdated to boot, let’s review your other suggestion…
No, it isn't utterly useless. It also shows you have tried to solve
the problem in a civil manner if you take it further.
“… after that [sic] the court system.”
[sic] refers to the missing comma.
So let me see if I understand correctly.
I run a pair of nameservers. Let’s call them ns1.company.com
<http://ns1.company.com/> and ns2.company.com <http://ns2.company.com/>Someone registers example.com <http://example.com/> and points NS records
in the COM zone at my
nameservers.I’m now supposed to seek judicial relief in order to compel them to stop
doing that?Small claims doesn’t process claims seeking injunctive relief. I suppose
I could
use a $1,500 or even $5,000 small claims case as a way to get their
attention,
but that’s kind of an abuse of the process. If I want an injunction, at
least
in California, I have to go to Superior court.Now, first, we have to figure out jursidiction. As a general rule,
jurisdiction
goes to the court which is responsible for the locale in which the event
takes
place or where the contract was entered into, or the jursidiction set by
the
contract. In this case, there’s no contract, so we have to look at where
the
event in question occurred. The problem is that the law hasn’t really
caught
up with technology in this area and depending on who ends up being parties
to the suit, the definition gets pretty murky at best. Is it the primary
office of the registry? The registrar? The registrant? The location of the
nameserver(s) which are erroneously pointed to? (What if they are anycast
all over the world?) The business address of the operator or owner of
those
nameservers? Where, exactly do we file this suit?
Your lawyer will work that out.
The next problem we have is who to sue. Do we sue the domain registrant?
The
registrar they used to register the domain name? etc.
Your lawyer will work that out.
Yeah, I don’t think there’s enough possibility of any sort of recovery to
make that worth the effort or expense.
So you decide to not avail yourself of the process available to you. That
is not the same thing as saying there is no process.
I would have expected that the resulting NXDOMAIN replies from ns1 and ns2
would usually make this a self-correcting problem.
Are there actually people who do this misconfiguration on a zone big enough
for the traffic to matter, and leave it that way for very long before they
clue in that things aren't working right? I'd think that if somebody points
billy-bobs-bait-tackle-and-internet.com at you, it might take you quite some
time to notice - and if somebody whoopsies and points ebay.com's NS records
at you, the resulting disfunction would be noticed fairly soon....
(Miscreants who do this intentionally are, of course, a totally different
kettle of fish, and need to be dealt with as micreants....)
Once upon a time, Mark Andrews <marka@isc.org> said:
The following is general and is not directed at Cloudflare. I know
some people don't think errors in the reverse DNS are not critical
but if you are delegated a zone it is your responsablity to ensure
your servers are correctly serving that zone regardless of where
it is in the DNS heirarchy. Failure to do that causes additional
work for recursive servers. If you don't want to serve a zone then
remove the delegation.You are assuming that an authoritative server operator has some way to
know all the zones people delegate to their servers, and remove such
delegations if they don't want to handle them. That is a wrong
assumption.They have methods. They choose not to use them. See RFC 1033
COMPLAINTS then after that the court system.Mark
Let us review this and compare to your statement…
From RFC 1033:
COMPLAINTS
These are the suggested steps you should take if you are having
problems that you believe are caused by someone else's name server:1. Complain privately to the responsible person for the domain. You
can find their mailing address in the SOA record for the domain.2. Complain publicly to the responsible person for the domain.
3. Ask the NIC for the administrative person responsible for the
domain. Complain. You can also find domain contacts on the NIC in
the file NETINFO:DOMAIN-CONTACTS.TXT4. Complain to the parent domain authorities.
5. Ask the parent authorities to excommunicate the domain.
1. Doesn’t really apply in a situation where someone has pointed
an NS record for a domain at your server without warning. There
is no SOA record from which to retrieve said mailing address.If they have pointed a NS record at you there is a SOA record. Either
in the zone or in the delegating zone.
Sure, but most likely this isn’t particularly useful… See below.
Also doesn’t work very well in cases where the SOA record does
not contain a valid email address that reaches someone.Some do, some don't. There is also whois address, web contact addresses
etc.
Sometimes, if you’re lucky, if it all works as intended and the person isn’t
using domain privacy…
2. Do we really want NANOG buried in “Will the
@#@!@$!@$% who delegated XYZ.COM <.xyz Domain Names | Join Generation XYZ; <.xyz Domain Names | Join Generation XYZ; NS Records to
point to
my servers <name> and <name> please cease and desist?”
messages? Personally, I vote no.Why not. It is a operational message about a misconfiguration.
Because NANOG isn’t for solving individual misconfigurations. It’s for
discussing issues on the internet requiring coordination.
This doesn’t require coordination of multiple providers, it’s a simple
bug report.
It would significantly raise the N in SNR IMHO. Your opinion may differ.
I still vote no.
3. The NIC? Please explicate Mr. Andrews what that would mean
in the modern era. Please cover both the normal case and
the cases where domain privacy is configured.4. This might _MIGHT_ actually work, but I suspect that $REGISTRY
is unlikely to help much when $REGISTRAR accepted an NS record
from one of their customers for a domain they registered
that happens to point to your server. Similarly, I suspect
$REGISTRAR is going to tell you that they won’t make changes
without authorization from the domain owner.The registrar becomes party to the disruption to your services and
no the contract the registry signed with ICANN does not save them
from being fined by a court further down the process so they should
listen as it is their finanical interests to listen.
What disruption? It’s pretty hard to argue that sending back some
SERVFAIL responses as a result of a few errant packets on UDP/53
constitutes a significant disruption to service.
Criminal law trumps contract law and deliberate disruption to
services falls under criminal law. It becomes deliberate once they
fail to act on the complaint in a timely manner. Remember we are
dealing with matters of fact here. Published NS records and address
records.
Sure, but to get a DA to prosecute for deliberate disruption, one has
to be able to prove intent. Mere misconfiguration is not intent.
Mere misconfiguration followed by ignoring bug reports becomes a little
more grey, but I bet you’re still not likely to get very far without
a much larger disruption to your service in the form of time spent
than you suffer by simply ignoring it.
Add to that there are published proceedures that are not being
followed that they should be aware of.
Published procedures don’t have the force of law. They may help you
to create a presumption of misconduct or negligence, but that’s about
as far as they can go.
5. I suspect that success in this effort will likely parallel
the level of success I would expect in step 4.So, now that we’ve realized that RFC-1033 is utterly useless in this
context and badly outdated to boot, let’s review your other suggestion…No, it isn't utterly useless. It also shows you have tried to solve
the problem in a civil manner if you take it further.
It has a less than 0.001% probability of achieving a useful end result.
I consider that within the realm of “utterly useless”. YMMV.
“… after that [sic] the court system.”
[sic] refers to the missing comma.
So let me see if I understand correctly.
I run a pair of nameservers. Let’s call them ns1.company.com
<http://ns1.company.com/> and ns2.company.com <http://ns2.company.com/>Someone registers example.com <http://example.com/> and points NS records
in the COM zone at my
nameservers.I’m now supposed to seek judicial relief in order to compel them to stop
doing that?Small claims doesn’t process claims seeking injunctive relief. I suppose
I could
use a $1,500 or even $5,000 small claims case as a way to get their
attention,
but that’s kind of an abuse of the process. If I want an injunction, at
least
in California, I have to go to Superior court.Now, first, we have to figure out jursidiction. As a general rule,
jurisdiction
goes to the court which is responsible for the locale in which the event
takes
place or where the contract was entered into, or the jursidiction set by
the
contract. In this case, there’s no contract, so we have to look at where
the
event in question occurred. The problem is that the law hasn’t really
caught
up with technology in this area and depending on who ends up being parties
to the suit, the definition gets pretty murky at best. Is it the primary
office of the registry? The registrar? The registrant? The location of the
nameserver(s) which are erroneously pointed to? (What if they are anycast
all over the world?) The business address of the operator or owner of
those
nameservers? Where, exactly do we file this suit?Your lawyer will work that out.
OK, so let me make sure I’m understanding you correctly.
I’m getting these extra packets I don’t want. They’re probably costing me
less than $1/day, but they’re a bit annoying.
You now want me to go pay someone $300/hour to sort all of this out, probably
against a $5,000 or $10,000 retainer just to start?
Will you be financing any of these operations, or, are you just hoping that
we’re all dumb enough to bankrupt ourselves in the name of clean DNS?
The next problem we have is who to sue. Do we sue the domain registrant?
The
registrar they used to register the domain name? etc.Your lawyer will work that out.
See above.
Yeah, I don’t think there’s enough possibility of any sort of recovery to
make that worth the effort or expense.So you decide to not avail yourself of the process available to you. That
is not the same thing as saying there is no process.
I never said there was no process. I said that the existing process was useless.
If the procedural argument doesn’t convince you and the economic argument doesn’t
sink in, then, you are entitled to your opinion, but I’m willing to bet that a
much larger fraction of the community believes that there is nothing to be gained
from the process compared to the costs of engaging in it.
Owen
I run a pair of nameservers. Let’s call them ns1.company.com
and ns2.company.comSomeone registers example.com and points NS records in the COM zone at my
nameservers.I would have expected that the resulting NXDOMAIN replies from ns1 and ns2
would usually make this a self-correcting problem.
You don’t get NXDOMAIN when a nameserver gets a request for a zone it doesn’t
serve.
You either get SERVFAIL or you get NS records back as a referral.
Are there actually people who do this misconfiguration on a zone big enough
for the traffic to matter, and leave it that way for very long before they
clue in that things aren't working right? I'd think that if somebody points
billy-bobs-bait-tackle-and-internet.com at you, it might take you quite some
time to notice - and if somebody whoopsies and points ebay.com's NS records
at you, the resulting disfunction would be noticed fairly soon….
Depends on your definition of “matter”.
Also, misconfiguring one important zone doesn’t necessarily generate significantly
more traffic than generating a whole lot of unimportant ones. Especially if
you misconfigure zones in ip6.arpa or in-addr.arpa as was the case at the
beginning of this topic.
(Miscreants who do this intentionally are, of course, a totally different
kettle of fish, and need to be dealt with as micreants....)
Yep, though one has to wonder why they would bother.
Owen
>
>
>>>
>>>
>>>> Once upon a time, Mark Andrews <marka@isc.org> said:
>>>>> The following is general and is not directed at Cloudflare. I know
>>>>> some people don't think errors in the reverse DNS are not critical
>>>>> but if you are delegated a zone it is your responsablity to ensure
>>>>> your servers are correctly serving that zone regardless of where
>>>>> it is in the DNS heirarchy. Failure to do that causes additional
>>>>> work for recursive servers. If you don't want to serve a zone then
>>>>> remove the delegation.
>>>>
>>>> You are assuming that an authoritative server operator has some way
to
>>>> know all the zones people delegate to their servers, and remove such
>>>> delegations if they don't want to handle them. That is a wrong
>>>> assumption.
>>>
>>> They have methods. They choose not to use them. See RFC 1033
>>> COMPLAINTS then after that the court system.
>>>
>>> Mark
>>
>> Let us review this and compare to your statement…
>>
>> From RFC 1033:
>>> COMPLAINTS
>>>
>>> These are the suggested steps you should take if you are having
>>> problems that you believe are caused by someone else's name server:
>>>
>>>
>>> 1. Complain privately to the responsible person for the domain.
You
>>> can find their mailing address in the SOA record for the domain.
>>>
>>> 2. Complain publicly to the responsible person for the domain.
>>>
>>> 3. Ask the NIC for the administrative person responsible for the
>>> domain. Complain. You can also find domain contacts on the NIC in
>>> the file NETINFO:DOMAIN-CONTACTS.TXT
>>>
>>> 4. Complain to the parent domain authorities.
>>>
>>> 5. Ask the parent authorities to excommunicate the domain.
>>
>> 1. Doesn’t really apply in a situation where someone has pointed
>> an NS record for a domain at your server without warning. There
>> is no SOA record from which to retrieve said mailing address.
>
> If they have pointed a NS record at you there is a SOA record. Either
> in the zone or in the delegating zone.Sure, but most likely this isn’t particularly useful… See below.
>
>> Also doesn’t work very well in cases where the SOA record does
>> not contain a valid email address that reaches someone.
>
> Some do, some don't. There is also whois address, web contact addresses
> etc.Sometimes, if you’re lucky, if it all works as intended and the person
isn’t using domain privacy…
Domain privacy is supposed to pass on operational and legal issues.
It isn't a get out of free card for not running a nameserver / zone
correctly.
>> 2. Do we really want NANOG buried in “Will the
>> @#@!@$!@$% who delegated XYZ.COM <.xyz Domain Names | Join Generation XYZ;
<.xyz Domain Names | Join Generation XYZ; NS Records to
>> point to
>> my servers <name> and <name> please cease and desist?”
>> messages? Personally, I vote no.
>
> Why not. It is a operational message about a misconfiguration.Because NANOG isn’t for solving individual misconfigurations. It’s for
discussing issues on the internet requiring coordination.This doesn’t require coordination of multiple providers, it’s a simple
bug report.It would significantly raise the N in SNR IMHO. Your opinion may differ.
I still vote no.
>> 3. The NIC? Please explicate Mr. Andrews what that would mean
>> in the modern era. Please cover both the normal case and
>> the cases where domain privacy is configured.
>>
>> 4. This might _MIGHT_ actually work, but I suspect that $REGISTRY
>> is unlikely to help much when $REGISTRAR accepted an NS record
>> from one of their customers for a domain they registered
>> that happens to point to your server. Similarly, I suspect
>> $REGISTRAR is going to tell you that they won’t make changes
>> without authorization from the domain owner.
>
> The registrar becomes party to the disruption to your services and
> no the contract the registry signed with ICANN does not save them
> from being fined by a court further down the process so they should
> listen as it is their finanical interests to listen.What disruption? It’s pretty hard to argue that sending back some
SERVFAIL responses as a result of a few errant packets on UDP/53
constitutes a significant disruption to service.
Owen you have zero knowledge of the volume or impact a configuration
error causes. Some are minor, some are not.
> Criminal law trumps contract law and deliberate disruption to
> services falls under criminal law. It becomes deliberate once they
> fail to act on the complaint in a timely manner. Remember we are
> dealing with matters of fact here. Published NS records and address
> records.Sure, but to get a DA to prosecute for deliberate disruption, one has
to be able to prove intent. Mere misconfiguration is not intent.
Mere misconfiguration followed by ignoring bug reports becomes a little
more grey, but I bet you’re still not likely to get very far without
a much larger disruption to your service in the form of time spent
than you suffer by simply ignoring it.
I suspect ignoring a certified letter complaining about the problem
with easily verifiable facts leads to easily provable intent.
> Add to that there are published proceedures that are not being
> followed that they should be aware of.Published procedures don’t have the force of law. They may help you
to create a presumption of misconduct or negligence, but that’s about
as far as they can go.
I agree they don't have the force of law but courts do pay attention
to them especially when one of the parties involved has tried to
follow them to avoid going to the courts in the first place.
>> 5. I suspect that success in this effort will likely parallel
>> the level of success I would expect in step 4.
>>
>> So, now that we’ve realized that RFC-1033 is utterly useless in this
>> context and badly outdated to boot, let’s review your other suggestion…
>
> No, it isn't utterly useless. It also shows you have tried to solve
> the problem in a civil manner if you take it further.It has a less than 0.001% probability of achieving a useful end result.
A made up statistic. I've had better success with errors at stage
1 than that, probably about 20% and no I don't have the records to
prove it.
> I run a pair of nameservers. Let???s call them ns1.company.com
> and ns2.company.com> Someone registers example.com and points NS records in the COM zone at my
> nameservers.I would have expected that the resulting NXDOMAIN replies from ns1 and ns2
would usually make this a self-correcting problem.Are there actually people who do this misconfiguration on a zone big enough
for the traffic to matter, and leave it that way for very long before they
clue in that things aren't working right? I'd think that if somebody points
billy-bobs-bait-tackle-and-internet.com at you, it might take you quite some
time to notice - and if somebody whoopsies and points ebay.com's NS records
at you, the resulting disfunction would be noticed fairly soon....
The recent example seems to be Digital Ocean who had 20k domains pointed
at their NS servers that weren't configured by customers. There is a
bit about it at
that may be interesting to read. I disagree with some of the analysis
but it's a reasonable insight into the frequency of this.
* owen@delong.com (Owen DeLong) [Wed 31 Aug 2016, 01:47 CEST]:
You don’t get NXDOMAIN when a nameserver gets a request for a zone it doesn’t serve.
Correct in most cases (there's an edge case where a server is [mis] configured as authoritative with its own empty . and its regular zones and allows global querying; it's similar to asking a root server for anything in a nonexistent TLD).
You either get SERVFAIL or you get NS records back as a referral.
Or REFUSED.
-- Niels.