Docs: notes on ETRN

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 9a52502d25a63dbde91e308424835722590dc5bc..745794a2a8bdae5bc02a66c58c9626ea0d980415 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -1764,6 +1764,12 @@ distributors have chosen to bundle different libraries with their packaged
 versions. However, the more recent releases seem to have standardized on the
 Berkeley DB library.
 
+.new
+Ownership of the Berkeley DB library has moved to a major corporation;
+development seems to have stalled and documentation is not freely available.
+This is probably not tenable for the long term use by Exim.
+.wen
+
 Different DBM libraries have different conventions for naming the files they
 use. When a program opens a file called &_dbmfile_&, there are several
 possibilities:
@@ -1852,6 +1858,17 @@ DBMLIB=/usr/local/lib/db-4.1/libdb.a
 There is further detailed discussion about the various DBM libraries in the
 file &_doc/dbm.discuss.txt_& in the Exim distribution.
 
+.new
+When moving from one DBM library to another,
+for the hints databases it suffices to just remove all the files in the
+directory named &"db/"& under the spool directory.
+This is because hints are only for optimisation and will be rebuilt
+during normal operations.
+Non-hints DBM databases (used by &"dbm"& lookups in the configuration)
+will need individual rebuilds for the new DBM library.
+This is not done automatically
+.wen
+
 
 
 .section "Pre-building configuration" "SECID25"
@@ -15187,8 +15204,11 @@ See section &<<SECDKIMVFY>>& for further details.
 
 .option acl_smtp_etrn main string&!! unset
 .cindex "ETRN" "ACL for"
+.cindex "ETRN" advertisement
 This option defines the ACL that is run when an SMTP ETRN command is
-received. See chapter &<<CHAPACL>>& for further details.
+received.
+If no value is set then the ETRN facility is not advertised.
+See chapter &<<CHAPACL>>& for further details.
 
 .option acl_smtp_expn main string&!! unset
 .cindex "EXPN" "ACL for"
@@ -37643,6 +37663,14 @@ RCPT failures.
 .subsection "The ETRN command" SECTETRN
 .cindex "ETRN" "processing"
 .cindex "ESMTP extensions" ETRN
+Most modern installations never need to use this.
+It is used for managing messages queued for an intermittently-connecting
+destination (eg. one using a dialup connection).
+
+.oindex "&%acl_smtp_etrn%&"
+The command is only available if permitted by an ACL
+specfied by the main-section &%acl_smtp_etrn%& option.
+
 RFC 1985 describes an ESMTP command called ETRN that is designed to
 overcome the security problems of the TURN command (which has fallen into
 disuse). When Exim receives an ETRN command on a TCP/IP connection, it runs
@@ -40255,8 +40283,6 @@ for remote hosts
 The &'misc'& database is used for
 
 .ilist
-Serializing ETRN runs (when &%smtp_etrn_serialize%& is set)
-.next
 Serializing delivery to a specific host (when &%serialize_hosts%& is set in an
 &(smtp)& transport)
 .next
@@ -40264,11 +40290,13 @@ Limiting the concurrency of specific transports (when &%max_parallel%& is set
 in a transport)
 .next
 Recording EHLO-time facilities advertised by hosts
+.next
+Serializing ETRN runs (when &%smtp_etrn_serialize%& is set)
 .endlist
 
 
 
-.section "exim_dumpdb" "SECTdumpdb"
+.subsection "exim_dumpdb" "SECTdumpdb"
 .cindex "&'exim_dumpdb'&"
 The entire contents of a database are written to the standard output by the
 &'exim_dumpdb'& program,
@@ -40310,7 +40338,7 @@ cross-references.
 
 
 
-.section "exim_tidydb" "SECTtidydb"
+.subsection "exim_tidydb" "SECTtidydb"
 .cindex "&'exim_tidydb'&"
 The &'exim_tidydb'& utility program is used to tidy up the contents of a hints
 database. If run with no options, it removes all records that are more than 30
@@ -40359,7 +40387,7 @@ databases is likely to keep on increasing.
 
 
 
-.section "exim_fixdb" "SECTfixdb"
+.subsection "exim_fixdb" "SECTfixdb"
 .cindex "&'exim_fixdb'&"
 The &'exim_fixdb'& program is a utility for interactively modifying databases.
 Its main use is for testing Exim, but it might also be occasionally useful for