--- /sys/netinet/libalias/libalias.3	Thu Jan 20 15:17:02 2005
+++ libalias.3	Thu Jan 31 17:09:19 2008
@@ -364,6 +364,31 @@
 An internal error within the packet aliasing engine occurred.
 .El
 .Ed
+.Pp
+.Ft int
+.Fn LibAliasOutTry "struct libalias *" "char *buffer" "int maxpacketsize" "int create"
+.Bd -ragged -offset indent
+This function is identical to
+.Fn LibAliasOut
+when
+.Fa create 
+argument is non-zero.
+When
+.Fa create 
+equals to zero, an outgoing packet coming from the local network to a remote
+machine is aliased only if a corresponding entry was found in the internal table
+of aliasing links.
+Otherwise,
+.Dv PKT_ALIAS_IGNORED
+code is returned to the caller.
+.Pp
+This is intended to be used by applications having several active
+.Nm
+instances at the same time and wishing to control whether new entries
+creation should be prohibited in certain circumstances.
+For example, this can be used for matching traffic against several
+instances' tables, where new entry should be created only in one of them.
+.Ed
 .Sh PORT AND ADDRESS REDIRECTION
 The functions described in this section allow machines on the local network
 to be accessible in some degree to new incoming connections from the external