Re: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
On 9/28/2023 1:56 PM, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote: What do you think that output is - the PTR is resolved to "localhost." You obviously did not get the point that I was making. Using ip6.arpa *is* the standard way to get around with "DNS-like" IPv6 addresses, as it would be "understood". Using the "ipv6-literal.net" domain is not portable and would result in NXDOMAIN anywhere but Windows (where the resolver seems to intercept and convert them internally). The ip6.arpa names are used to lookup PTR records which contain hostnames. The ipv6-literal.net names are used to simulate records and map the name to an IPv6 address (with an optional address scope). For those that are unaware of the history[1][2][3], UNC names support the use of IPv4 addresses as an alternative to SMB server names or DNS host names. End users expect to be able to specify a UNC path such as \\2001:db8:85a3:8d3:1319:8a2e:370:7348\share or \\[2001:db8:85a3:8d3:1319:8a2e:370:7348]\share However, colons are illegal in UNC paths and therefore standard IPv6 representations cannot be used. The .ipv6-literal.net server name is a method of representing an IPv6 address as a UNC server name such that it can be locally translated by getaddrinfo() into an IPv6 address without querying DNS. \\2001-db8-85a3-8d3-1319-8a2e-370-7348.ipv6-literal.net\share If the ipv6.arpa representation\\8.4.3.7.0.7.3.0.e.2.a.8.9.1.3.1.3.d.8.0.3.a.5.8.8.b.d.0.1.0.0.2.ip6.arpa\path was used as a server name and treated as a DNS lookup that would be harder for humans to construct and no more portable. The ip6.arpa representation would also be unable to represent IPv6 address scopes which are supported by ipv6-literal.net names. I am unaware of any Microsoft Windows APIs that can be called to translate from an IPv6 address to an ipv6-literal.net string. [1] https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names [2] https://devblogs.microsoft.com/oldnewthing/20100915-00/?p=12863 [3] https://learn.microsoft.com/en-us/windows/win32/api/winnetwk/nf-winnetwk-wnetaddconnection3a smime.p7s Description: S/MIME Cryptographic Signature -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation:https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
RE: [EXTERNAL] Re: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
> What do you think that output is - the PTR is resolved to "localhost." You obviously did not get the point that I was making. Using ip6.arpa *is* the standard way to get around with "DNS-like" IPv6 addresses, as it would be "understood". Using the "ipv6-literal.net" domain is not portable and would result in NXDOMAIN anywhere but Windows (where the resolver seems to intercept and convert them internally). Anton Lavrentiev Contractor NIH/NLM/NCBI -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation:https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
Re: [EXTERNAL] Re: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
On 2023-09-27 17:56, Lavrentiev, Anton (NIH/NLM/NCBI) [C] wrote: $ host -t ptr \ 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa domain name pointer localhost. I was talking about resolving the .ipv6-literal.net names via DNS. Such as "fe80--219-99ff-feae-73ce.ipv6-literal.net" What do you think that output is - the PTR is resolved to "localhost." I find *host* easier to use, script, and more tersely informative than the other bind DNS utilities: the bind-utils Cygwin package contains DNS utilities: delv dig host mdig named-rrchecker nslookup nsupdate and the lookups support most of the same arguments and options, with different names and defaults: host defaults to -t A -t -t MX, but host and nslookup only accept a single type, while dig accepts -t ANY; delv and mdig will do deep dives for DNSSEC and DNS; while named-rrchecker validates DNS RR inputs. -- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation:https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
RE: [EXTERNAL] Re: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
> $ host -t ptr I was talking about resolving the .ipv6-literal.net names via DNS. Such as "fe80--219-99ff-feae-73ce.ipv6-literal.net" Anton Lavrentiev Contractor NIH/NLM/NCBI -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation:https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
Re: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
On 2023-09-27 11:02, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
Does Cygwin (or Win32) have a function to convert "raw" ASCII IPv6 addresses
into *.ipv6-
literal.net per
Not hard to change ":" to "-" and append .ipv6-literal.net - in bash:
${addrv6//:/-}.ipv6-literal.net
$ getent ahosts -- --1.ipv6-literal.net
::1 STREAM ::1
::1 DGRAM ::1
If Windows API is documented to have such a function, you should be able find
it in the w32api package in Cygwin.
As for the "literal" representation, the only "standard" and documented IPv6
DNS notation is in the .ip6.arpa domain (the analog for IPv4's
"in-addr.arpa").
Microsoft seems to have uniquely "enhanced" that convention to use a more
compact notation... > Even though it says it resolves internally without DNS on
Windows, this
convention is not likely portable (and will cause an actual DNS hit on other
platforms that do not specially recognize ".ipv6-literal.net" -- unlike the
treatment of ".ip6.arpa").
And a likely result of that is going to be "NXDOMAIN" (domain does not
exist).
Just have to unstuff any "::" to enough ":...:" to make 8 groups, fill to 4
hex digits each, strip the ":"s then reverse the (hex) digits or vice versa, add
"."s after each, and add ip6.arpa e.g.
::1 ->
:::::::0001 ->
1000::::::: ->
1000 ->
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa
$ host -t ptr \
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa domain
name pointer localhost.
but there may be few PTR records set up or recognized for IP V6 addresses.
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut
-- Antoine de Saint-Exupéry
--
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RE: Cygwin/Win32 utility function to convert "raw" IPv6 address string into *.ipv6-literal.net string ?
> Does Cygwin (or Win32) have a function to convert "raw" ASCII IPv6 addresses > into *.ipv6- > literal.net per If Windows API is documented to have such a function, you should be able find it in the w32api package in Cygwin. As for the "literal" representation, the only "standard" and documented IPv6 DNS notation is in the .ip6.arpa domain (the analog for IPv4's "in-addr.arpa"). Microsoft seems to have uniquely "enhanced" that convention to use a more compact notation... Even though it says it resolves internally without DNS on Windows, this convention is not likely portable (and will cause an actual DNS hit on other platforms that do not specially recognize ".ipv6-literal.net" -- unlike the treatment of ".ip6.arpa"). And a likely result of that is going to be "NXDOMAIN" (domain does not exist). HTH, Anton Lavrentiev Contractor NIH/NLM/NCBI -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation:https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
