1 files changed, 43 insertions, 4 deletions

diff --git a/ssh_config.5 b/ssh_config.5
index b35753307..9c277a66f 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -127,8 +127,15 @@ Valid arguments are
 If set to
 .Dq yes ,
 passphrase/password querying will be disabled.
+In addition, the 
+.Cm ServerAliveInterval 
+and
+.Cm SetupTimeOut
+options will both be set to 300 seconds by default.
 This option is useful in scripts and other batch jobs where no user
-is present to supply the password.
+is present to supply the password,
+and where it is desirable to detect a
+broken network swiftly.
 The argument must be
 .Dq yes
 or
@@ -371,7 +378,8 @@ token used for the session will be set to expire after 20 minutes.
 Remote clients will be refused access after this time.
 .Pp
 The default is
-.Dq no .
+.Dq yes
+(Debian-specific).
 .Pp
 See the X11 SECURITY extension specification for full details on
 the restrictions imposed on untrusted clients.
@@ -710,8 +718,12 @@ from the server,
 will send a message through the encrypted
 channel to request a response from the server.
 The default
-is 0, indicating that these messages will not be sent to the server.
-This option applies to protocol version 2 only.
+is 0, indicating that these messages will not be sent to the server,
+or 300 if the
+.Cm BatchMode
+option is set.
+.Cm ProtocolKeepAlives
+is a Debian-specific compatibility alias for this option.
 .It Cm ServerAliveCountMax
 Sets the number of server alive messages (see above) which may be
 sent without
@@ -739,6 +751,27 @@ If, for example,
 .Cm ServerAliveCountMax
 is left at the default, if the server becomes unresponsive ssh
 will disconnect after approximately 45 seconds.
+This option works when using protocol version 2 only; in protocol version
+1 there is no mechanism to request a response from the server to the
+server alive messages, so disconnection is the responsibility of the TCP
+stack.
+.It Cm SetupTimeOut
+Normally,
+.Nm ssh
+blocks indefinitely whilst waiting to receive the ssh banner and other
+setup protocol from the server, during the session setup.
+This can cause
+.Nm ssh
+to hang under certain circumstances.
+If this option is set,
+.Nm ssh
+will give up if no data from the server is received for the specified
+number of seconds.
+The argument must be an integer.
+The default is 0 (disabled), or 300 if
+.Cm BatchMode
+is set.
+This is a Debian-specific option.
 .It Cm SmartcardDevice
 Specifies which smartcard device to use.
 The argument to this keyword is the device
@@ -786,6 +819,12 @@ Specifies whether the system should send TCP keepalive messages to the
 other side.
 If they are sent, death of the connection or crash of one
 of the machines will be properly noticed.
+This option only uses TCP keepalives (as opposed to using ssh level
+keepalives), so takes a long time to notice when the connection dies.
+As such, you probably want
+the
+.Cm ServerAliveInterval
+option as well.
 However, this means that
 connections will die if the route is down temporarily, and some people
 find it annoying.