upstream: document changed default for UpdateHostKeys

OpenBSD-Commit-ID: 25c390b21d142f78ac0106241d13441c4265fd2c

ssh_config.5

@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: ssh_config.5,v 1.319 2020/01/28 01:49:36 djm Exp $
-.Dd $Mdocdate: January 28 2020 $
+.\" $OpenBSD: ssh_config.5,v 1.320 2020/01/30 22:25:34 djm Exp $
+.Dd $Mdocdate: January 30 2020 $
 .Dt SSH_CONFIG 5
 .Os
 .Sh NAME
@@ -1678,13 +1678,22 @@ after authentication has completed and add them to
 The argument must be
 .Cm yes ,
 .Cm no
-(the default) or
+or
 .Cm ask .
-Enabling this option allows learning alternate hostkeys for a server
+This option allows learning alternate hostkeys for a server
 and supports graceful key rotation by allowing a server to send replacement
 public keys before old ones are removed.
 Additional hostkeys are only accepted if the key used to authenticate the
 host was already trusted or explicitly accepted by the user.
+.Pp
+.Cm UpdateHostKeys
+is enabled by default if the user has not overriden the default
+.Cm UserKnownHostsFile
+setting, otherwise
+.Cm UpdateHostKeys
+will be set to
+.Cm ask .
+.Pp
 If
 .Cm UpdateHostKeys
 is set to