- other parameters to be varied. Here is complete documentation for the
- available features:
-
- GnuTLS allows the caller to specify separate lists of permitted key
- exchange methods, main cipher algorithms, and MAC algorithms. These may be
- used in any combination to form a specific cipher suite. This is unlike
- OpenSSL, where complete cipher names can be passed to its control function.
- GnuTLS also allows a list of acceptable protocols to be supplied.
-
- For compatibility with OpenSSL, the tls_require_ciphers option can be set
- to complete cipher suite names such as RSA_ARCFOUR_SHA, but for GnuTLS this
- option controls only the cipher algorithms. Exim searches each item in the
- list for the name of an available algorithm. For example, if the list
- contains RSA_AES_SHA, then AES is recognized, and the behaviour is exactly
- the same as if just AES were given.
-
- There are additional options called gnutls_require_kx, gnutls_require_mac,
- and gnutls_require_protocols that can be used to restrict the key exchange
- methods, MAC algorithms, and protocols, respectively. These options are
- ignored if OpenSSL is in use.
-
- All four options are available as global options, controlling how Exim
- behaves as a server, and also as options of the smtp transport, controlling
- how Exim behaves as a client. All the values are string expanded. After
- expansion, the values must be colon-separated lists, though the separator
- can be changed in the usual way.
-
- Each of the four lists starts out with a default set of algorithms. If the
- first item in one of the "require" options does _not_ start with an
- exclamation mark, all the default items are deleted. In this case, only
- those that are explicitly specified can be used. If the first item in one
- of the "require" items _does_ start with an exclamation mark, the defaults
- are left on the list.
-
- Then, any item that starts with an exclamation mark causes the relevant
- entry to be removed from the list, and any item that does not start with an
- exclamation mark causes a new entry to be added to the list. Unrecognized
- items in the list are ignored. Thus:
-
- tls_require_ciphers = !ARCFOUR
-
- allows all the defaults except ARCFOUR, whereas
-
- tls_require_ciphers = AES : 3DES
-
- allows only cipher suites that use AES or 3DES. For tls_require_ciphers
- the recognized names are AES_256, AES_128, AES (both of the preceding),
- 3DES, ARCFOUR_128, ARCFOUR_40, and ARCFOUR (both of the preceding). The
- default list does not contain all of these; it just has AES_256, AES_128,
- 3DES, and ARCFOUR_128.
-
- For gnutls_require_kx, the recognized names are DHE_RSA, RSA (which
- includes DHE_RSA), DHE_DSS, and DHE (which includes both DHE_RSA and
- DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA.
-
- For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and
- MD5. The default list contains SHA, MD5.
-
- For gnutls_require_protocols, the recognized names are TLS1 and SSL3.
- The default list contains TLS1, SSL3.
-
- In a server, the order of items in these lists is unimportant. The server
- will advertise the availability of all the relevant cipher suites. However,
- in a client, the order in the tls_require_ciphers list specifies a
- preference order for the cipher algorithms. The first one in the client's
- list that is also advertised by the server is tried first.
-
- 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. You must
- not set this option unless you really, really, really understand what you
- are doing. No pre-compiled distributions of Exim should ever set this
- option. When it is set, Exim compiles a runtime option called
- disable_fsync. If this is set true, Exim no longer calls fsync() to force
- updated files' data to be written to disc. Unexpected events such as
- crashes and power outages may cause data to be lost or scrambled. Beware.
-
- When ENABLE_DISABLE_FSYNC is not set, a reference to disable_fsync in a
- runtime configuration generates an "unknown option" error.
-
- 5. There is a new variable called $smtp_count_at_connection_start. The name
- is deliberately long, in order to emphasize what the contents are. This
- variable is set greater than zero only in processes spawned by the Exim
- daemon for handling incoming SMTP connections. When the daemon accepts a
- new connection, it increments this variable. A copy of the variable is
- passed to the child process that handles the connection, but its value is
- fixed, and never changes. It is only an approximation of how many incoming
- connections there actually are, because many other connections may come and
- go while a single connection is being processed. When a child process
- terminates, the daemon decrements the variable.
+ other parameters to be varied.
+
+ 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
+ set, Exim compiles a runtime option called disable_fsync.
+
+ 5. There is a new variable called $smtp_count_at_connection_start.
+
+ 6. There's a new control called no_pipelining.
+
+ 7. There are two new variables called $sending_ip_address and $sending_port.
+ These are set whenever an SMTP connection to another host has been set up.
+
+ 8. The expansion of the helo_data option in the smtp transport now happens
+ after the connection to the server has been made.
+
+ 9. There is a new expansion operator ${rfc2047d: that decodes strings that
+ are encoded as per RFC 2047.
+
+10. There is a new log selector called "pid", which causes the current process
+ id to be added to every log line, in square brackets, immediately after the
+ time and date.
+
+11. Exim has been modified so that it flushes SMTP output before implementing
+ a delay in an ACL. It also flushes the output before performing a callout,
+ as this can take a substantial time. These behaviours can be disabled by
+ obeying control = no_delay_flush or control = no_callout_flush,
+ respectively, at some earlier stage of the connection.
+
+12. There are two new expansion conditions that iterate over a list. They are
+ called forany and forall.
+
+13. There's a new global option called dsn_from that can be used to vary the
+ contents of From: lines in bounces and other automatically generated
+ messages ("delivery status notifications" - hence the name of the option).
+
+14. The smtp transport has a new option called hosts_avoid_pipelining.
+
+15. By default, exigrep does case-insensitive matches. There is now a -I option
+ that makes it case-sensitive.
+
+16. A number of new features ("addresses", "map", "filter", and "reduce") have
+ been added to string expansions to make it easier to process lists of
+ items, typically addresses.
+
+17. There's a new ACL modifier called "continue". It does nothing of itself,
+ and processing of the ACL always continues with the next condition or
+ modifier. It is provided so that the side effects of expanding its argument
+ can be used.
+
+18. It is now possible to use newline and other control characters (those with
+ values less than 32, plus DEL) as separators in lists.
+
+19. The exigrep utility now has a -v option, which inverts the matching
+ condition.
+
+20. The host_find_failed option in the manualroute router can now be set to
+ "ignore".
git://git.exim.org / users / jgh / exim.git / blobdiff