liable to incompatible change.
-Brightmail AntiSpam (BMI) suppport
+Brightmail AntiSpam (BMI) support
--------------------------------------------------------------
Brightmail AntiSpam is a commercial package. Please see
1) Adding support for BMI at compile time
To compile with BMI support, you need to link Exim against
- the Brighmail client SDK, consisting of a library
+ the Brightmail client SDK, consisting of a library
(libbmiclient_single.so) and a header file (bmi_api.h).
You'll also need to explicitly set a flag in the Makefile to
include BMI support in the Exim binary. Both can be achieved
-Sender Policy Framework (SPF) support
---------------------------------------------------------------
-
-To learn more about SPF, visit http://www.openspf.org. This
-document does not explain the SPF fundamentals, you should
-read and understand the implications of deploying SPF on your
-system before doing so.
-
-SPF support is added via the libspf2 library. Visit
-
- http://www.libspf2.org/
-
-to obtain a copy, then compile and install it. By default,
-this will put headers in /usr/local/include and the static
-library in /usr/local/lib.
-
-To compile Exim with SPF support, set these additional flags in
-Local/Makefile:
-
-EXPERIMENTAL_SPF=yes
-CFLAGS=-DSPF -I/usr/local/include
-EXTRALIBS_EXIM=-L/usr/local/lib -lspf2
-
-This assumes that the libspf2 files are installed in
-their default locations.
-
-You can now run SPF checks in incoming SMTP by using the "spf"
-ACL condition in either the MAIL, RCPT or DATA ACLs. When
-using it in the RCPT ACL, you can make the checks dependent on
-the RCPT address (or domain), so you can check SPF records
-only for certain target domains. This gives you the
-possibility to opt-out certain customers that do not want
-their mail to be subject to SPF checking.
-
-The spf condition takes a list of strings on its right-hand
-side. These strings describe the outcome of the SPF check for
-which the spf condition should succeed. Valid strings are:
-
- o pass The SPF check passed, the sending host
- is positively verified by SPF.
- o fail The SPF check failed, the sending host
- is NOT allowed to send mail for the domain
- in the envelope-from address.
- o softfail The SPF check failed, but the queried
- domain can't absolutely confirm that this
- is a forgery.
- o none The queried domain does not publish SPF
- records.
- o neutral The SPF check returned a "neutral" state.
- This means the queried domain has published
- a SPF record, but wants to allow outside
- servers to send mail under its domain as well.
- This should be treated like "none".
- o permerror This indicates a syntax error in the SPF
- record of the queried domain. You may deny
- messages when this occurs. (Changed in 4.83)
- o temperror This indicates a temporary error during all
- processing, including Exim's SPF processing.
- You may defer messages when this occurs.
- (Changed in 4.83)
- o err_temp Same as permerror, deprecated in 4.83, will be
- removed in a future release.
- o err_perm Same as temperror, deprecated in 4.83, will be
- removed in a future release.
-
-You can prefix each string with an exclamation mark to invert
-its meaning, for example "!fail" will match all results but
-"fail". The string list is evaluated left-to-right, in a
-short-circuit fashion. When a string matches the outcome of
-the SPF check, the condition succeeds. If none of the listed
-strings matches the outcome of the SPF check, the condition
-fails.
-
-Here is an example to fail forgery attempts from domains that
-publish SPF records:
-
-/* -----------------
-deny message = $sender_host_address is not allowed to send mail from ${if def:sender_address_domain {$sender_address_domain}{$sender_helo_name}}. \
- Please see http://www.openspf.org/Why?scope=${if def:sender_address_domain {mfrom}{helo}};identity=${if def:sender_address_domain {$sender_address}{$sender_helo_name}};ip=$sender_host_address
- spf = fail
---------------------- */
-
-You can also give special treatment to specific domains:
-
-/* -----------------
-deny message = AOL sender, but not from AOL-approved relay.
- sender_domains = aol.com
- spf = fail:neutral
---------------------- */
-
-Explanation: AOL publishes SPF records, but is liberal and
-still allows non-approved relays to send mail from aol.com.
-This will result in a "neutral" state, while mail from genuine
-AOL servers will result in "pass". The example above takes
-this into account and treats "neutral" like "fail", but only
-for aol.com. Please note that this violates the SPF draft.
-
-When the spf condition has run, it sets up several expansion
-variables.
-
- $spf_header_comment
- This contains a human-readable string describing the outcome
- of the SPF check. You can add it to a custom header or use
- it for logging purposes.
-
- $spf_received
- This contains a complete Received-SPF: header that can be
- added to the message. Please note that according to the SPF
- draft, this header must be added at the top of the header
- list. Please see section 10 on how you can do this.
-
- Note: in case of "Best-guess" (see below), the convention is
- to put this string in a header called X-SPF-Guess: instead.
-
- $spf_result
- This contains the outcome of the SPF check in string form,
- one of pass, fail, softfail, none, neutral, permerror or
- temperror.
-
- $spf_smtp_comment
- This contains a string that can be used in a SMTP response
- to the calling party. Useful for "fail".
-
-In addition to SPF, you can also perform checks for so-called
-"Best-guess". Strictly speaking, "Best-guess" is not standard
-SPF, but it is supported by the same framework that enables SPF
-capability. Refer to http://www.openspf.org/FAQ/Best_guess_record
-for a description of what it means.
-
-To access this feature, simply use the spf_guess condition in place
-of the spf one. For example:
-
-/* -----------------
-deny message = $sender_host_address doesn't look trustworthy to me
- spf_guess = fail
---------------------- */
-
-In case you decide to reject messages based on this check, you
-should note that although it uses the same framework, "Best-guess"
-is NOT SPF, and therefore you should not mention SPF at all in your
-reject message.
-
-When the spf_guess condition has run, it sets up the same expansion
-variables as when spf condition is run, described above.
-
-Additionally, since Best-guess is not standardized, you may redefine
-what "Best-guess" means to you by redefining spf_guess variable in
-global config. For example, the following:
-
-/* -----------------
-spf_guess = v=spf1 a/16 mx/16 ptr ?all
---------------------- */
-
-would relax host matching rules to a broader network range.
-
-
SRS (Sender Rewriting Scheme) Support
--------------------------------------------------------------
Exiscan currently includes SRS support via Miles Wilton's
libsrs_alt library. The current version of the supported
-library is 0.5.
+library is 0.5, there are reports of 1.0 working.
In order to use SRS, you must get a copy of libsrs_alt from
-http://srs.mirtol.com/
+https://opsec.eu/src/srs/
+
+(not the original source, which has disappeared.)
Unpack the tarball, then refer to MTAs/README.EXIM
to proceed. You need to set
in your Local/Makefile.
+
DCC Support
--------------------------------------------------------------
+Distributed Checksum Clearinghouse; http://www.rhyolite.com/dcc/
*) Building exim
mout-xforward.gmx.net 82.165.159.12
mout.gmx.net 212.227.15.16
-Use a reasonable IP. eg. one the sending cluster acutally uses.
+Use a reasonable IP. eg. one the sending cluster actually uses.
DMARC Support
--------------------------------------------------------------
2. Use the following global settings to configure DMARC:
-Required:
+Optional:
dmarc_tld_file Defines the location of a text file of valid
top level domains the opendmarc library uses
during domain parsing. Maintained by Mozilla,
the most current version can be downloaded
from a link at http://publicsuffix.org/list/.
+ If unset, "/etc/exim/opendmarc.tlds" (hardcoded)
+ is used.
Optional:
dmarc_history_file Defines the location of a file to log results
configure a dmarc_forensic_sender because the default sender address
construction might be inadequate.
- control = dmarc_forensic_enable
+ control = dmarc_enable_forensic
(AGAIN: You can choose not to send these forensic reports by simply
-not putting the dmarc_forensic_enable control line at any point in
+not putting the dmarc_enable_forensic control line at any point in
your exim config. If you don't tell it to send them, it will not
send them.)
deny dmarc_status = reject
!authenticated = *
- message = Message from $domain_used_domain failed sender's DMARC policy, REJECT
-
-
-
-Transport post-delivery actions
---------------------------------------------------------------
-
-An arbitrary per-transport string can be expanded on successful delivery,
-and (for SMTP transports) a second string on deferrals caused by a host error.
-This feature may be used, for example, to write exim internal log information
-(not available otherwise) into a database.
-
-In order to use the feature, you must set
-
-EXPERIMENTAL_TPDA=yes
-
-in your Local/Makefile
-
-and define the expandable strings in the runtime config file, to
-be executed at end of delivery.
-
-Additionally, there are 6 more variables, available at end of
-delivery:
-
-tpda_delivery_ip IP of host, which has accepted delivery
-tpda_delivery_port Port of remote host which has accepted delivery
-tpda_delivery_fqdn FQDN of host, which has accepted delivery
-tpda_delivery_local_part local part of address being delivered
-tpda_delivery_domain domain part of address being delivered
-tpda_delivery_confirmation SMTP confirmation message
-
-In case of a deferral caused by a host-error:
-tpda_defer_errno Error number
-tpda_defer_errstr Error string possibly containing more details
-
-The $router_name and $transport_name variables are also usable.
-
-
-To take action after successful deliveries, set the following option
-on any transport of interest.
-
-tpda_delivery_action
-
-An example might look like:
-
-tpda_delivery_action = \
-${lookup pgsql {SELECT * FROM record_Delivery( \
- '${quote_pgsql:$sender_address_domain}',\
- '${quote_pgsql:${lc:$sender_address_local_part}}', \
- '${quote_pgsql:$tpda_delivery_domain}', \
- '${quote_pgsql:${lc:$tpda_delivery_local_part}}', \
- '${quote_pgsql:$tpda_delivery_ip}', \
- '${quote_pgsql:${lc:$tpda_delivery_fqdn}}', \
- '${quote_pgsql:$message_exim_id}')}}
-
-The string is expanded after the delivery completes and any
-side-effects will happen. The result is then discarded.
-Note that for complex operations an ACL expansion can be used.
-
-
-In order to log host deferrals, add the following option to an SMTP
-transport:
-
-tpda_host_defer_action
-
-This is a private option of the SMTP transport. It is intended to
-log failures of remote hosts. It is executed only when exim has
-attempted to deliver a message to a remote host and failed due to
-an error which doesn't seem to be related to the individual
-message, sender, or recipient address.
-See section 47.2 of the exim documentation for more details on how
-this is determined.
-
-Example:
-
-tpda_host_defer_action = \
-${lookup mysql {insert into delivlog set \
- msgid = '${quote_mysql:$message_exim_id}', \
- senderlp = '${quote_mysql:${lc:$sender_address_local_part}}', \
- senderdom = '${quote_mysql:$sender_address_domain}', \
- delivlp = '${quote_mysql:${lc:$tpda_delivery_local_part}}', \
- delivdom = '${quote_mysql:$tpda_delivery_domain}', \
- delivip = '${quote_mysql:$tpda_delivery_ip}', \
- delivport = '${quote_mysql:$tpda_delivery_port}', \
- delivfqdn = '${quote_mysql:$tpda_delivery_fqdn}', \
- deliverrno = '${quote_mysql:$tpda_defer_errno}', \
- deliverrstr = '${quote_mysql:$tpda_defer_errstr}' \
- }}
-
-
-Redis Lookup
---------------------------------------------------------------
-
-Redis is open source advanced key-value data store. This document
-does not explain the fundamentals, you should read and understand how
-it works by visiting the website at http://www.redis.io/.
-
-Redis lookup support is added via the hiredis library. Visit:
-
- https://github.com/redis/hiredis
-
-to obtain a copy, or find it in your operating systems package repository.
-If building from source, this description assumes that headers will be in
-/usr/local/include, and that the libraries are in /usr/local/lib.
-
-1. In order to build exim with Redis lookup support add
-
-EXPERIMENTAL_REDIS=yes
-
-to your Local/Makefile. (Re-)build/install exim. exim -d should show
-Experimental_Redis in the line "Support for:".
-
-EXPERIMENTAL_REDIS=yes
-LDFLAGS += -lhiredis
-# CFLAGS += -I/usr/local/include
-# LDFLAGS += -L/usr/local/lib
-
-The first line sets the feature to include the correct code, and
-the second line says to link the hiredis libraries into the
-exim binary. The commented out lines should be uncommented if you
-built hiredis from source and installed in the default location.
-Adjust the paths if you installed them elsewhere, but you do not
-need to uncomment them if an rpm (or you) installed them in the
-package controlled locations (/usr/include and /usr/lib).
-
-
-2. Use the following global settings to configure Redis lookup support:
-
-Required:
-redis_servers This option provides a list of Redis servers
- and associated connection data, to be used in
- conjunction with redis lookups. The option is
- only available if Exim is configured with Redis
- support.
-
-For example:
-
-redis_servers = 127.0.0.1/10/ - using database 10 with no password
-redis_servers = 127.0.0.1//password - to make use of the default database of 0 with a password
-redis_servers = 127.0.0.1// - for default database of 0 with no password
-
-3. Once you have the Redis servers defined you can then make use of the
-experimental Redis lookup by specifying ${lookup redis{}} in a lookup query.
-
-4. Example usage:
-
-(Host List)
-hostlist relay_from_ips = <\n ${lookup redis{SMEMBERS relay_from_ips}}
-
-Where relay_from_ips is a Redis set which contains entries such as "192.168.0.0/24" "10.0.0.0/8" and so on.
-The result set is returned as
-192.168.0.0/24
-10.0.0.0/8
-..
-.
-
-(Domain list)
-domainlist virtual_domains = ${lookup redis {HGET $domain domain}}
-
-Where $domain is a hash which includes the key 'domain' and the value '$domain'.
-
-(Adding or updating an existing key)
-set acl_c_spammer = ${if eq{${lookup redis{SPAMMER_SET}}}{OK}}
-
-Where SPAMMER_SET is a macro and it is defined as
-
-"SET SPAMMER <some_value>"
-
-(Getting a value from Redis)
+ message = Message from $dmarc_used_domain failed sender's DMARC policy, REJECT
-set acl_c_spam_host = ${lookup redis{GET...}}
-
-
-Proxy Protocol Support
---------------------------------------------------------------
-
-Exim now has Experimental "Proxy Protocol" support. It was built on
-specifications from:
-http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt
-Above URL revised May 2014 to change version 2 spec:
-http://git.1wt.eu/web?p=haproxy.git;a=commitdiff;h=afb768340c9d7e50d8e
-
-The purpose of this function is so that an application load balancer,
-such as HAProxy, can sit in front of several Exim servers and Exim
-will log the IP that is connecting to the proxy server instead of
-the IP of the proxy server when it connects to Exim. It resets the
-$sender_address_host and $sender_address_port to the IP:port of the
-connection to the proxy. It also re-queries the DNS information for
-this new IP address so that the original sender's hostname and IP
-get logged in the Exim logfile. There is no logging if a host passes or
-fails Proxy Protocol negotiation, but it can easily be determined and
-recorded in an ACL (example is below).
-
-1. To compile Exim with Proxy Protocol support, put this in
-Local/Makefile:
-
-EXPERIMENTAL_PROXY=yes
-
-2. Global configuration settings:
-
-proxy_required_hosts = HOSTLIST
-
-The proxy_required_hosts option will require any IP in that hostlist
-to use Proxy Protocol. The specification of Proxy Protocol is very
-strict, and if proxy negotiation fails, Exim will not allow any SMTP
-command other than QUIT. (See end of this section for an example.)
-The option is expanded when used, so it can be a hostlist as well as
-string of IP addresses. Since it is expanded, specifying an alternate
-separator is supported for ease of use with IPv6 addresses.
-
-To log the IP of the proxy in the incoming logline, add:
- log_selector = +proxy
-
-A default incoming logline (wrapped for appearance) will look like this:
-
- 2013-11-04 09:25:06 1VdNti-0001OY-1V <= me@example.net
- H=mail.example.net [1.2.3.4] P=esmtp S=433
-
-With the log selector enabled, an email that was proxied through a
-Proxy Protocol server at 192.168.1.2 will look like this:
-
- 2013-11-04 09:25:06 1VdNti-0001OY-1V <= me@example.net
- H=mail.example.net [1.2.3.4] P=esmtp PRX=192.168.1.2 S=433
-
-3. In the ACL's the following expansion variables are available.
-
-proxy_host_address The (internal) src IP of the proxy server
- making the connection to the Exim server.
-proxy_host_port The (internal) src port the proxy server is
- using to connect to the Exim server.
-proxy_target_address The dest (public) IP of the remote host to
- the proxy server.
-proxy_target_port The dest port the remote host is using to
- connect to the proxy server.
-proxy_session Boolean, yes/no, the connected host is required
- to use Proxy Protocol.
-
-There is no expansion for a failed proxy session, however you can detect
-it by checking if $proxy_session is true but $proxy_host is empty. As
-an example, in my connect ACL, I have:
-
- warn condition = ${if and{ {bool{$proxy_session}} \
- {eq{$proxy_host_address}{}} } }
- log_message = Failed required proxy protocol negotiation \
- from $sender_host_name [$sender_host_address]
-
- warn condition = ${if and{ {bool{$proxy_session}} \
- {!eq{$proxy_host_address}{}} } }
- # But don't log health probes from the proxy itself
- condition = ${if eq{$proxy_host_address}{$sender_host_address} \
- {false}{true}}
- log_message = Successfully proxied from $sender_host_name \
- [$sender_host_address] through proxy protocol \
- host $proxy_host_address
-
- # Possibly more clear
- warn logwrite = Remote Source Address: $sender_host_address:$sender_host_port
- logwrite = Proxy Target Address: $proxy_target_address:$proxy_target_port
- logwrite = Proxy Internal Address: $proxy_host_address:$proxy_host_port
- logwrite = Internal Server Address: $received_ip_address:$received_port
-
-
-4. Recommended ACL additions:
- - Since the real connections are all coming from your proxy, and the
- per host connection tracking is done before Proxy Protocol is
- evaluated, smtp_accept_max_per_host must be set high enough to
- handle all of the parallel volume you expect per inbound proxy.
- - With the smtp_accept_max_per_host set so high, you lose the ability
- to protect your server from massive numbers of inbound connections
- from one IP. In order to prevent your server from being DOS'd, you
- need to add a per connection ratelimit to your connect ACL. I
- suggest something like this:
-
- # Set max number of connections per host
- LIMIT = 5
- # Or do some kind of IP lookup in a flat file or database
- # LIMIT = ${lookup{$sender_host_address}iplsearch{/etc/exim/proxy_limits}}
-
- defer message = Too many connections from this IP right now
- ratelimit = LIMIT / 5s / per_conn / strict
-
-
-5. Runtime issues to be aware of:
- - The proxy has 3 seconds (hard-coded in the source code) to send the
- required Proxy Protocol header after it connects. If it does not,
- the response to any commands will be:
- "503 Command refused, required Proxy negotiation failed"
- - If the incoming connection is configured in Exim to be a Proxy
- Protocol host, but the proxy is not sending the header, the banner
- does not get sent until the timeout occurs. If the sending host
- sent any input (before the banner), this causes a standard Exim
- synchronization error (i.e. trying to pipeline before PIPELINING
- was advertised).
- - This is not advised, but is mentioned for completeness if you have
- a specific internal configuration that you want this: If the Exim
- server only has an internal IP address and no other machines in your
- organization will connect to it to try to send email, you may
- simply set the hostlist to "*", however, this will prevent local
- mail programs from working because that would require mail from
- localhost to use Proxy Protocol. Again, not advised!
-
-6. Example of a refused connection because the Proxy Protocol header was
-not sent from a host configured to use Proxy Protocol. In the example,
-the 3 second timeout occurred (when a Proxy Protocol banner should have
-been sent), the banner was displayed to the user, but all commands are
-rejected except for QUIT:
-
-# nc mail.example.net 25
-220-mail.example.net, ESMTP Exim 4.82+proxy, Mon, 04 Nov 2013 10:45:59
-220 -0800 RFC's enforced
-EHLO localhost
-503 Command refused, required Proxy negotiation failed
-QUIT
-221 mail.example.net closing connection
-
-
-DSN Support
---------------------------------------------------------------
-
-DSN Support tries to add RFC 3461 support to Exim. It adds support for
-*) the additional parameters for MAIL FROM and RCPT TO
-*) RFC complient MIME DSN messages for all of
- success, failure and delay notifications
-*) dsn_advertise_hosts main option to select which hosts are able
- to use the extension
-*) dsn_lasthop router switch to end DSN processing
-
-In case of failure reports this means that the last three parts, the message body
-intro, size info and final text, of the defined template are ignored since there is no
-logical place to put them in the MIME message.
-
-All the other changes are made without changing any defaults
-
-Building exim:
---------------
-
-Define
-EXPERIMENTAL_DSN=YES
-in your Local/Makefile.
-
-Configuration:
---------------
-All DSNs are sent in MIME format if you built exim with EXPERIMENTAL_DSN=YES
-No option needed to activate it, and no way to turn it off.
-
-Failure and delay DSNs are triggered as usual except a sender used NOTIFY=...
-to prevent them.
-
-Support for Success DSNs is added and activated by NOTIFY=SUCCESS by clients.
-
-Add
-dsn_advertise_hosts = *
-or a more restrictive host_list to announce DSN in EHLO answers
-
-Those hosts can then use NOTIFY,ENVID,RET,ORCPT options.
-
-If a message is relayed to a DSN aware host without changing the envelope
-recipient the options are passed along and no success DSN is generated.
-
-A redirect router will always trigger a success DSN if requested and the DSN
-options are not passed any further.
-
-A success DSN always contains the recipient address as submitted by the
-client as required by RFC. Rewritten addresses are never exposed.
-
-If you used DSN patch up to 1.3 before remove all "dsn_process" switches from
-your routers since you don't need them anymore. There is no way to "gag"
-success DSNs anymore. Announcing DSN means answering as requested.
-
-You can prevent Exim from passing DSN options along to other DSN aware hosts by defining
-dsn_lasthop
-in a router. Exim will then send the success DSN himself if requested as if
-the next hop does not support DSN.
-Adding it to a redirect router makes no difference.
-
-
-Certificate name checking
---------------------------------------------------------------
-The X509 certificates used for TLS are supposed be verified
-that they are owned by the expected host. The coding of TLS
-support to date has not made these checks.
-
-If built with EXPERIMENTAL_CERTNAMES defined, code is
-included to do so, and a new smtp transport option
-"tls_verify_cert_hostname" supported which takes a list of
-names for which the checks must be made. The host must
-also be in "tls_verify_hosts".
-
-Both Subject and Subject-Alternate-Name certificate fields
-are supported, as are wildcard certificates (limited to
-a single wildcard being the initial component of a 3-or-more
-component FQDN).
DANE
by (a) is thought to be smaller than that of the set
of root CAs.
+It also allows the server to declare (implicitly) that
+connections to it should use TLS. An MITM could simply
+fail to pass on a server's STARTTLS.
+
DANE scales better than having to maintain (and
side-channel communicate) copies of server certificates
for every possible target server. It also scales
operation of DANE.
The TLSA record for the server may have "certificate
-usage" of DANE_TA(2) or DANE_EE(3). The latter specifies
+usage" of DANE-TA(2) or DANE-EE(3). The latter specifies
the End Entity directly, i.e. the certificate involved
is that of the server (and should be the sole one transmitted
during the TLS handshake); this is appropriate for a
single system, using a self-signed certificate.
- DANE_TA usage is effectively declaring a specific CA
+ DANE-TA usage is effectively declaring a specific CA
to be used; this might be a private CA or a public,
well-known one. A private CA at simplest is just
a self-signed certificate which is used to sign
If a public CA is used then all clients must be primed with it
(losing one advantage of DANE) - but the attack surface is
reduced from all public CAs to that single CA.
-DANE_TA is commonly used for several services and/or
+DANE-TA is commonly used for several services and/or
servers, each having a TLSA query-domain CNAME record,
all of which point to a single TLSA record.
are workable for 4th-field hashes.
-For use with the DANE_TA model, server certificates
+For use with the DANE-TA model, server certificates
must have a correct name (SubjectName or SubjectAltName).
The use of OCSP-stapling should be considered, allowing
for fast revocation of certificates (which would otherwise
be limited by the DNS TTL on the TLSA records). However,
-this is likely to only be usable with DANE_TA. NOTE: the
-default is to request OCSP for all hosts; the certificate
-chain in DANE_EE usage will be insufficient to validate
-the OCSP proof and verification will fail. Either disable
-OCSP completely or use the (new) variable $tls_out_tlsa_usage
-like so:
-
- hosts_request_ocsp = ${if or { {= {4}{$tls_out_tlsa_usage}} \
- {= {0}{$tls_out_tlsa_usage}} } \
+this is likely to only be usable with DANE-TA. NOTE: the
+default of requesting OCSP for all hosts is modified iff
+DANE is in use, to:
+
+ hosts_request_ocsp = ${if or { {= {0}{$tls_out_tlsa_usage}} \
+ {= {4}{$tls_out_tlsa_usage}} } \
{*}{}}
-The variable is a bitfield with numbered bits set for TLSA
-record usage codes. The zero above means DANE was not in use,
-the four means that only DANE_TA usage TLSA records were
-found. If the definition of hosts_require_ocsp or
-hosts_request_ocsp includes the string "tls_out_tlsa_usage",
-they are re-expanded in time to control the OCSP request.
-[ All a bit complicated. Should we make that definition
-the default? Should we override the user's definition? ]
+The (new) variable $tls_out_tlsa_usage is a bitfield with
+numbered bits set for TLSA record usage codes.
+The zero above means DANE was not in use,
+the four means that only DANE-TA usage TLSA records were
+found. If the definition of hosts_request_ocsp includes the
+string "tls_out_tlsa_usage", they are re-expanded in time to
+control the OCSP request.
+
+This modification of hosts_request_ocsp is only done if
+it has the default value of "*". Admins who change it, and
+those who use hosts_require_ocsp, should consider the interaction
+with DANE in their OCSP settings.
For client-side DANE there are two new smtp transport options,
-hosts_try_dane and hosts_require_dane. They do the obvious thing.
+hosts_try_dane and hosts_require_dane.
[ should they be domain-based rather than host-based? ]
+Hosts_require_dane will result in failure if the target host
+is not DNSSEC-secured.
+
DANE will only be usable if the target host has DNSSEC-secured
MX, A and TLSA records.
-(TODO: specify when fallback happens vs. when the host is not used)
+A TLSA lookup will be done if either of the above options match
+and the host-lookup succeeded using dnssec.
+If a TLSA lookup is done and succeeds, a DANE-verified TLS connection
+will be required for the host. If it does not, the host will not
+be used; there is no fallback to non-DANE or non-TLS.
-If dane is in use the following transport options are ignored:
+If DANE is requested and useable (see above) the following transport
+options are ignored:
+ hosts_require_tls
tls_verify_hosts
tls_try_verify_hosts
tls_verify_certificates
tls_crl
tls_verify_cert_hostnames
+If DANE is not usable, whether requested or not, and CA-anchored
+verification evaluation is wanted, the above variables should be set
+appropriately.
+
Currently dnssec_request_domains must be active (need to think about that)
and dnssec_require_domains is ignored.
There is a new variable $tls_out_dane which will have "yes" if
verification succeeded using DANE and "no" otherwise (only useful
-in combination with EXPERIMENTAL_TPDA), and a new variable
+in combination with EXPERIMENTAL_EVENT), and a new variable
$tls_out_tlsa_usage (detailed above).
+Under GnuTLS, DANE is only supported from versin 3.0.0 onwards
+
+
+
+DSN extra information
+---------------------
+If compiled with EXPERIMENTAL_DSN_INFO extra information will be added
+to DSN fail messages ("bounces"), when available. The intent is to aid
+tracing of specific failing messages, when presented with a "bounce"
+complaint and needing to search logs.
+
+
+The remote MTA IP address, with port number if nonstandard.
+Example:
+ Remote-MTA: X-ip; [127.0.0.1]:587
+Rationale:
+ Several addresses may correspond to the (already available)
+ dns name for the remote MTA.
+
+The remote MTA connect-time greeting.
+Example:
+ X-Remote-MTA-smtp-greeting: X-str; 220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000
+Rationale:
+ This string sometimes presents the remote MTA's idea of its
+ own name, and sometimes identifies the MTA software.
+
+The remote MTA response to HELO or EHLO.
+Example:
+ X-Remote-MTA-helo-response: X-str; 250-the.local.host.name Hello localhost [127.0.0.1]
+Limitations:
+ Only the first line of a multiline response is recorded.
+Rationale:
+ This string sometimes presents the remote MTA's view of
+ the peer IP connecting to it.
+
+The reporting MTA detailed diagnostic.
+Example:
+ X-Exim-Diagnostic: X-str; SMTP error from remote mail server after RCPT TO:<d3@myhost.test.ex>: 550 hard error
+Rationale:
+ This string sometimes give extra information over the
+ existing (already available) Diagnostic-Code field.
+
+
+Note that non-RFC-documented field names and data types are used.
+
+
+LMDB Lookup support
+-------------------
+LMDB is an ultra-fast, ultra-compact, crash-proof key-value embedded data store.
+It is modeled loosely on the BerkeleyDB API. You should read about the feature
+set as well as operation modes at https://symas.com/products/lightning-memory-mapped-database/
+
+LMDB single key lookup support is provided by linking to the LMDB C library.
+The current implementation does not support writing to the LMDB database.
+
+Visit https://github.com/LMDB/lmdb to download the library or find it in your
+operating systems package repository.
+
+If building from source, this description assumes that headers will be in
+/usr/local/include, and that the libraries are in /usr/local/lib.
+
+1. In order to build exim with LMDB lookup support add or uncomment
+
+EXPERIMENTAL_LMDB=yes
+
+to your Local/Makefile. (Re-)build/install exim. exim -d should show
+Experimental_LMDB in the line "Support for:".
+
+EXPERIMENTAL_LMDB=yes
+LDFLAGS += -llmdb
+# CFLAGS += -I/usr/local/include
+# LDFLAGS += -L/usr/local/lib
+
+The first line sets the feature to include the correct code, and
+the second line says to link the LMDB libraries into the
+exim binary. The commented out lines should be uncommented if you
+built LMDB from source and installed in the default location.
+Adjust the paths if you installed them elsewhere, but you do not
+need to uncomment them if an rpm (or you) installed them in the
+package controlled locations (/usr/include and /usr/lib).
+
+2. Create your LMDB files, you can use the mdb_load utility which is
+part of the LMDB distribution our your favourite language bindings.
+
+3. Add the single key lookups to your exim.conf file, example lookups
+are below.
+
+${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}{$value}}
+${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}{$value}fail}
+${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}}
+
+
+Queuefile transport
+-------------------
+Queuefile is a pseudo transport which does not perform final delivery.
+It simply copies the exim spool files out of the spool directory into
+an external directory retaining the exim spool format.
+
+The spool files can then be processed by external processes and then
+requeued into exim spool directories for final delivery.
+
+The motivation/inspiration for the transport is to allow external
+processes to access email queued by exim and have access to all the
+information which would not be available if the messages were delivered
+to the process in the standard email formats.
+
+The mailscanner package is one of the processes that can take advantage
+of this transport to filter email.
+
+The transport can be used in the same way as the other existing transports,
+i.e by configuring a router to route mail to a transport configured with
+the queuefile driver.
+
+The transport only takes one option:
+
+* directory - This is used to specify the directory messages should be
+copied to
+
+The generic transport options (body_only, current_directory, disable_logging,
+debug_print, delivery_date_add, envelope_to_add, event_action, group,
+headers_add, headers_only, headers_remove, headers_rewrite, home_directory,
+initgroups, max_parallel, message_size_limit, rcpt_include_affixes,
+retry_use_local_part, return_path, return_path_add, shadow_condition,
+shadow_transport, transport_filter, transport_filter_timeout, user) are
+ignored.
+
+Sample configuration:
+
+(Router)
+
+scan:
+ driver = accept
+ transport = scan
+
+(Transport)
+
+scan:
+ driver = queuefile
+ directory = /var/spool/baruwa-scanner/input
+
+
+In order to build exim with Queuefile transport support add or uncomment
+
+EXPERIMENTAL_QUEUEFILE=yes
+
+to your Local/Makefile. (Re-)build/install exim. exim -d should show
+Experimental_QUEUEFILE in the line "Support for:".
+
--------------------------------------------------------------
End of file
git://git.exim.org / users / heiko / exim.git / blobdiff