X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/9775396084feef071a7c565d6d9b42839ae6098e..4eb9d6ef85652741d2852f89365a0af08ddc382e:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index 4521d7dd9..aae58c631 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -6,23 +6,189 @@ Before a formal release, there may be quite a lot of detail so that people can test from the snapshots or the CVS before the documentation is updated. Once the documentation is updated, this file is reduced to a short list. -Version 4.78 +Version 4.81 +------------ + + 1. New command-line option -bI:sieve will list all supported sieve extensions + of this Exim build on standard output, one per line. + ManageSieve (RFC 5804) providers managing scripts for use by Exim should + query this to establish the correct list to include in the protocol's + SIEVE capability line. + + 2. If the -n option is combined with the -bP option, then the name of an + emitted option is not output, only the value (if visible to you). + For instance, "exim -n -bP pid_file_path" should just emit a pathname + followed by a newline, and no other text. + + 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now + has a "tls_dh_min_bits" option, to set the minimum acceptable number of + bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites) + acceptable for security. (Option accepted but ignored if using OpenSSL). + Defaults to 1024, the old value. May be lowered only to 512, or raised as + far as you like. Raising this may hinder TLS interoperability with other + sites and is not currently recommended. Lowering this will permit you to + establish a TLS session which is not as secure as you might like. + + Unless you really know what you are doing, leave it alone. + + 4. If not built with DISABLE_DNSSEC, Exim now has the main option + dns_use_dnssec; if set to 1 then Exim will initialise the resolver library + to send the DO flag to your recursive resolver. If you have a recursive + resolver, which can set the Authenticated Data (AD) flag in results, Exim + can now detect this. + + Current status: work-in-progress; $sender_host_dnssec variable added. + + 5. DSCP support for outbound connections: on a transport using the smtp driver, + set "dscp = ef", for instance, to cause the connections to have the relevant + DSCP (IPv4 TOS or IPv6 TCLASS) value in the header. + + Similarly for inbound connections, there is a new control modifier, dscp, + so "warn control = dscp/ef" in the connect ACL, or after authentication. + + Supported values depend upon system libraries. "exim -bI:dscp" to list the + ones Exim knows of. You can also set a raw number 0..0x3F. + + 6. The -G command-line flag is no longer ignored; it is now equivalent to an + ACL setting "control = suppress_local_fixups". The -L command-line flag + is now accepted and forces use of syslog, with the provided tag as the + process name. A few other flags used by Sendmail are now accepted and + ignored. + + 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery" + ACL modifier; works for single-recipient mails which are recieved on and + deliverable via SMTP. Using the connection made for a recipient verify, + if requested before the verify, or a new one made for the purpose while + the inbound connection is still active. The bulk of the mail item is copied + direct from the inbound socket to the outbound (as well as the spool file). + When the source notifies the end of data, the data acceptance by the destination + is negociated before the acceptance is sent to the source. If the destination + does not accept the mail item, for example due to content-scanning, the item + is not accepted from the source and therefore there is no need to generate + a bounce mail. This is of benefit when providing a secondary-MX service. + The downside is that delays are under the control of the ultimate destination + system not your own. + + The Recieved-by: header on items delivered by cutthrough is generated + early in of reception rather than at the end; this will affect any timestamp + included. The log line showing delivery is recorded before that showing + reception; it uses a new ">>" tag instead of "=>". + + To support the feature, verify-callout connections can now use ESMTP and TLS. + The usual smtp transport options are honoured, plus a (new, default everything) + hosts_verify_avoid_tls. + + New variable families named tls_in_cipher, tls_out_cipher etc. are introduced + for specific access to the information for each connection. The old names + are present for now but deprecated. + + Not yet supported: IGNOREQUOTA, SIZE, PIPELINING, AUTH. + + +Version 4.80 ------------ 1. New authenticator driver, "gsasl". Server-only (at present). This is a SASL interface, licensed under GPL, which can be found at http://www.gnu.org/software/gsasl/. This system does not provide sources of data for authentication, so - careful use needs to be made of the conditions in Exim. Note that - this can not yet be used as a drop-in replacement for Cyrus SASL, as - Exim is currently unable to construct strings with embedded NULs for - use as keys in lookups against sasldb2. + careful use needs to be made of the conditions in Exim. 2. New authenticator driver, "heimdal_gssapi". Server-only. A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME is no longer honoured for setuid programs by Heimdal. Use the "server_keytab" option to point to the keytab. + 3. The "pkg-config" system can now be used when building Exim to reference + cflags and library information for lookups and authenticators, rather + than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and + "LOOKUP_LIBS" directly. Similarly for handling the TLS library support + without adjusting "TLS_INCLUDE" and "TLS_LIBS". + + In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to + find the headers and libraries for PCRE. + + 4. New expansion variable $tls_bits. + + 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will + be joined together with ASCII NUL characters to construct the key to pass + into the DBM library. Can be used with gsasl to access sasldb2 files as + used by Cyrus SASL. + + 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1. + + Avoid release 1.0.1a if you can. Note that the default value of + "openssl_options" is no longer "+dont_insert_empty_fragments", as that + increased susceptibility to attack. This may still have interoperability + implications for very old clients (see version 4.31 change 37) but + administrators can choose to make the trade-off themselves and restore + compatibility at the cost of session security. + + 7. Use of the new expansion variable $tls_sni in the main configuration option + tls_certificate will cause Exim to re-expand the option, if the client + sends the TLS Server Name Indication extension, to permit choosing a + different certificate; tls_privatekey will also be re-expanded. You must + still set these options to expand to valid files when $tls_sni is not set. + + The SMTP Transport has gained the option tls_sni, which will set a hostname + for outbound TLS sessions, and set $tls_sni too. + + A new log_selector, +tls_sni, has been added, to log received SNI values + for Exim as a server. + + 8. The existing "accept_8bitmime" option now defaults to true. This means + that Exim is deliberately not strictly RFC compliant. We're following + Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default. + Those who disagree, or know that they are talking to mail servers that, + even today, are not 8-bit clean, need to turn off this option. + + 9. Exim can now be started with -bw (with an optional timeout, given as + -bw). With this, stdin at startup is a socket that is + already listening for connections. This has a more modern name of + "socket activation", but forcing the activated socket to fd 0. We're + interested in adding more support for modern variants. + +10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix + for numbers indicates multiplication by 1024^3. + +11. The GnuTLS support has been revamped; the three options gnutls_require_kx, + gnutls_require_mac & gnutls_require_protocols are no longer supported. + tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority + string, documentation for which is at: + http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html + + SNI support has been added to Exim's GnuTLS integration too. + + For sufficiently recent GnuTLS libraries, ${randint:..} will now use + gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness. + +12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file + is now available. If the contents of the file are valid, then Exim will + send that back in response to a TLS status request; this is OCSP Stapling. + Exim will not maintain the contents of the file in any way: administrators + are responsible for ensuring that it is up-to-date. + + See "experimental-spec.txt" for more details. + +13. ${lookup dnsdb{ }} supports now SPF record types. They are handled + identically to TXT record lookups. + +14. New expansion variable $tod_epoch_l for higher-precision time. + +15. New global option tls_dh_max_bits, defaulting to current value of NSS + hard-coded limit of DH ephemeral bits, to fix interop problems caused by + GnuTLS 2.12 library recommending a bit count higher than NSS supports. + +16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier. + Option can now be a path or an identifier for a standard prime. + If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23". + Set to "historic" to get the old GnuTLS behaviour of auto-generated DH + primes. + +17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS). + Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL + install was not built with OPENSSL_NO_SSL2 ("no-ssl2"). + Version 4.77 ------------