Date: Fri, 27 Dec 2013 23:06:16 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r259973 - head/etc Message-ID: <201312272306.rBRN6GON067322@svn.freebsd.org>
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Author: delphij Date: Fri Dec 27 23:06:15 2013 New Revision: 259973 URL: http://svnweb.freebsd.org/changeset/base/259973 Log: Tighten default restrictions for ntpd(8) server and provide a link to NTP access restriction documentation. The new default restrictions would allow only time queries from a remote system and will KoD all other requests, but still allow localhost to do make all requests. These restrictions are also recommended for all Internet-facing public NTP servers. This changeset is intended for an instant MFC to stable/10 and releng/10.0. Modified: head/etc/ntp.conf Modified: head/etc/ntp.conf ============================================================================== --- head/etc/ntp.conf Fri Dec 27 23:00:56 2013 (r259972) +++ head/etc/ntp.conf Fri Dec 27 23:06:15 2013 (r259973) @@ -17,7 +17,7 @@ # users with a static IP and good upstream NTP servers to add a server # to the pool. See http://www.pool.ntp.org/join.html if you are interested. # -# The option `iburst' is used for faster initial synchronisation. +# The option `iburst' is used for faster initial synchronization. # server 0.freebsd.pool.ntp.org iburst server 1.freebsd.pool.ntp.org iburst @@ -35,21 +35,37 @@ server 2.freebsd.pool.ntp.org iburst # server 2.CC.pool.ntp.org iburst # -# Security: Only accept NTP traffic from the following hosts. -# The following configuration example only accepts traffic from the -# above defined servers. +# Security: +# +# By default, only allow time queries and block all other requests +# from unauthenticated clients. +# +# See http://support.ntp.org/bin/view/Support/AccessRestrictions +# for more information. +# +restrict default kod nomodify notrap nopeer noquery +restrict -6 default kod nomodify notrap nopeer noquery +# +# Alternatively, the following rules would block all unauthorized access. +# +#restrict default ignore +#restrict -6 default ignore +# +# In this case, all remote NTP time servers also need to be explicitly +# allowed or they would not be able to exchange time information with +# this server. # # Please note that this example doesn't work for the servers in # the pool.ntp.org domain since they return multiple A records. -# (This is the reason that by default they are commented out) # -#restrict default ignore #restrict 0.pool.ntp.org nomodify nopeer noquery notrap #restrict 1.pool.ntp.org nomodify nopeer noquery notrap #restrict 2.pool.ntp.org nomodify nopeer noquery notrap -#restrict 127.0.0.1 -#restrict -6 ::1 -#restrict 127.127.1.0 +# +# The following settings allow unrestricted access from the localhost +restrict 127.0.0.1 +restrict -6 ::1 +restrict 127.127.1.0 # # If a server loses sync with all upstream servers, NTP clients
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