X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/preload-hacks/blobdiff_plain/99222954396fb6ad618fea50123c5fa565b78ed6..9111857cc67644ff89749d5919647b38033bb6fd:/noip.1

diff --git a/noip.1 b/noip.1
index 8ab355f..f4598da 100644
--- a/noip.1
+++ b/noip.1
@@ -86,8 +86,8 @@ is set, then the file it names is read instead (assuming it exists; if
 it doesn't, no configuration is read).
 .PP
 The configuration file has a simple line-based format.  A line is
-ignored if it consists only of whitespace, or if its first whitespace
-character is
+ignored if it consists only of whitespace, or if its first
+non-whitespace character is
 .RB ` # '.
 Otherwise, the first whitespace-delimited word is a keyword and the
 remainder of the line is a value.  The following keywords are
@@ -123,9 +123,10 @@ variable
 can also be used to control which ports are assigned automatically.
 .TP
 .BI "realbind " acl-entry
-Add an entry to the
+Add a comma-separated list of entries to the
 .B realbind
-access control list (ACL).  When a program attempts to
+access control list (ACL).  (See below for the format of an ACL entry.)
+When a program attempts to
 .BR bind (2)
 a socket to an address, the
 .B realbind
@@ -148,9 +149,10 @@ are also put at the end (before the
 rules), though this may change later.
 .TP
 .BI "realconnect " acl-entry
-Add an entry to the
+Add a comma-separated list of entries to the
 .B realconnect
-access control list (ACL).  When a program attempts to
+access control list (ACL).  (See below for the format of an ACL entry.)
+When a program attempts to
 .BR connect (2)
 a socket to an address, or to contact another socket using
 .BR sendto (2)
@@ -175,7 +177,7 @@ rules are appended on the end.  Currently, the rules in
 are also put at the end (before the
 .B _AFTER
 rules), though this may change later.
-.PP
+.IP
 (Aside: An attempt to connect to a remote host may not be a hopeless failure,
 even if a real IP socket is denied:
 .B noip
@@ -183,22 +185,55 @@ deliberately makes no attempt to check that addresses being bound to
 sockets correspond to locally available addresses; and besides, sockets
 can be introduced into the directory by other programs simulating remote
 servers.)
+.TP
+.BI "impbind " bind-rule
+Add a comma-separated list of entries to the implicit-bind rule list.
+When a program attempts to transmit from a socket \(en e.g., with
+.BR connect (2),
+.BR sendto (2), or
+.BR sendmsg (2)
+\(en without binding its local address first,
+.B noip
+consults this list to decide on the correct local address to assign.
+Each entry in the list has the form
+.RS
+.IP
+.I address-range
+.IR address | \c
+.B same
+.PP
+The rules are tried in order: if the remote address matches (in the same
+way as in an ACL entry) the address range on the left side of the rule,
+then the socket is bound to the address from the right side; if the
+address on the right is
+.B same
+then the remote address is used.
+.PP
+Three environment variables
+are consulted too:
+.BR NOIP_IMPBIND_BEFORE ,
+.BR NOIP_IMPBIND ,
+and
+.BR NOIP_IMPBIND_AFTER .
+The
+.B _BEFORE
+rules are inserted at the front of the list; the
+.B _AFTER
+rules are appended on the end.  Currently, the rules in
+.B NOIP_IMPBIND
+are also put at the end (before the
+.B _AFTER
+rules), though this may change later.
+.RE
 .PP
 An
 .I acl-entry
 is a comma-separated list of entries of the form:
 .IP
 .BR + | \-
-.IR address \c
-.RB [ \- \c
-.IR address | \c
-.BR / \c
-.IR prefix-length ]| \c
-.BR local | any
+.I address-range
 .RB [ : \c
-.IR port [ \c
-.BI \- \c
-.IR port ]]
+.IR port-range ]
 .PP
 (The spaces in the above are optional.)
 .PP
@@ -209,7 +244,9 @@ or
 .I denied
 .RB (` \- ').
 .PP
-The IP-address portion may be any of the following
+The
+.I address-range
+portion may be any of the following.
 .TP
 .B any
 Matches all addresses.
@@ -231,8 +268,9 @@ over octets to the right.
 .IB address / prefix-length
 Matches an address in the given network.
 .PP
-The port portion may be omitted (which means `match any port'), or may
-be a single
+The
+.I port-range
+may be omitted (which means `match any port'), or may be a single
 .I port
 or a range
 .IB port \- port