Changes BIND 9.15+ source distribution (gz -> xz, and SHA1 deprecation)

[icecream-guy]

Hi,

the BIND 9 development team has decided to change the compression method for BIND 9.15.7, and also for the next BIND 9.16.0 release to widely available **xz** compression algorithm.  Therefore, the tarball extension has changed from https://downloads.isc.org/isc/bind9/9.15.7/bind-9.15.7.tar.gz to https://downloads.isc.org/isc/bind9/9.15.7/bind-9.15.7.tar.xz

xz offers considerable savings in terms of disk space and thus network traffic and the tool is available in the base system for most if not all Linux and BSD distributions.

The previous versions of BIND 9 (9.11 and 9.14) are still distributed compressed with gzip.

The other change we will introduce early next year (timed with BIND 9.16.0 release) is the deprecation of SHA1 checksums.  The MD based algorithms are no longer collision resistant enough and henceforth the SHA1 based checksums no longer bear any real value.

Ondrej
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Ondřej Surý
ondrej@isc.org