[Dnsmasq-discuss] Fwd: Errors in address FQDN name combinations with hyphens

[Petr Menšík]

Those name can be checked by idn2 tool even without resolving them.

idn2 -d adrian---egn.000webhostapp.com.

does not report an error, so this host should work in dnsmasq.

But:

idn2 -- -h.example.org

idn2: toAscii: string start/ends with forbidden hyphen

I think we may even straight refuse those invalid names on arrival and
return just status: REFUSED as reply. Maybe with a possibility to
disable such check.

On 4/23/22 20:26, Dan Schaper via Dnsmasq-discuss wrote:
> The domain names in the second screenshot are IDNs, conversion of
> unicode to ascii. See
> https://en.wikipedia.org/wiki/Internationalized_domain_name#Example_of_IDNA_encoding
> for more on that.
> The ones in the first screenshot that generate errors also appear to
> be valid.
>
> Running 0p-1pvdwjev-qele.exactag.com through
> https://dns.google/query?name=0p-1pvdwjev-qele.exactag.com and
> http://sqa.fyicenter.com/1000207_Domain_Name_Validator.html both show
> that domain as valid and Google resolves it to an  IP address.
> Checking to see if the error is from line 2 that rolls over to line 3
> shows valid again
> https://dns.google/query?name=adrian---egn.000webhostapp.com.
>
> The first listed domain name zzz.eric-prautsch.com is very valid. Just
> like the single hyphen in my domain name.
>
> Let me know if there is a question on that list, DeveloperDan is a
> good friend of ours at Pi-hole.
>
> Best,
> Dan
>
> mito mito wrote on 4/23/2022 4:14 AM:
>>
>> Hello Friends,
>>
>> I would appreciate your help on this problem.
>>
>> I have been using dnsmasq for a couple of years as an home ad/track
>> blocker and in the latest update available for debian bullseye
>> *dnsmasq-base/stable,now 2.85-1 armhf* *dnsmasq/stable, now 2.85-1
>> all* I have experienced a strange case that occurs with certain
>> combinations of names with a mid-hyphen, an error occurs but not in
>> all cases.
>>
>> From this list 
>>
>> For example names with double or triple hyphens names with hyphen and
>> dot 
>> Captura de pantalla de 2022-04-23 13-02-41.png
>>
>> In this case the error appears on line 3, if I comment or remove one
>> of the dashes the error appears on line 4 and so on
>>
>> However in this case there are no errors 
>> Captura de pantalla de 2022-04-23 13-06-31.png
>>
>> These are lists obtained from
>> https://www.github.developerdan.com/hosts/lists/ads-and-tracking-extended.txt
>>
>> Thank you
>> Greetings
>>
>>
>> _______________________________________________
>> Dnsmasq-discuss mailing list
>> Dnsmasq-discuss at lists.thekelleys.org.uk
>> https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>
>
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-- 
Petr Menšík
Software Engineer
Red Hat, http://www.redhat.com/
email: pemensik at redhat.com
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB
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