For details see:
http://ftp.isc.org/isc/bind9/9.11.7/RELEASE-NOTES-bind-9.11.7.html
"Security Fixes
The TCP client quota set using the tcp-clients option could be exceeded in some cases.
This could lead to exhaustion of file descriptors.
This flaw is disclosed in CVE-2018-5743. [GL #615]"
Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org> Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>