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-rw-r--r--doc/doc-docbook/spec.xfpt103
-rw-r--r--doc/doc-txt/ChangeLog4
-rw-r--r--doc/doc-txt/experimental-spec.txt145
3 files changed, 106 insertions, 146 deletions
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 73887d4e7..6096e1df2 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -12033,6 +12033,16 @@ qualified host name. See also &$smtp_active_hostname$&.
.new
+.vitem &$proxy_host_address$& &&&
+ &$proxy_host_port$& &&&
+ &$proxy_target_address$& &&&
+ &$proxy_target_port$& &&&
+ &$proxy_session$&
+These variables are only available when built with Proxy Protocol support
+For details see chapter &<<SECTproxyInbound>>&.
+.wen
+
+.new
.vitem &$prdr_requested$&
.cindex "PRDR" "variable for"
This variable is set to &"yes"& if PRDR was requested by the client for the
@@ -13469,6 +13479,7 @@ listed in more than one group.
.row &%helo_verify_hosts%& "HELO hard-checked for these hosts"
.row &%host_lookup%& "host name looked up for these hosts"
.row &%host_lookup_order%& "order of DNS and local name lookups"
+.row &%hosts_proxy%& "use proxy protocol for these hosts"
.row &%host_reject_connection%& "reject connection from these hosts"
.row &%hosts_treat_as_local%& "useful in some cluster configurations"
.row &%local_scan_timeout%& "timeout for &[local_scan()]&"
@@ -14824,6 +14835,14 @@ If the &%smtp_connection%& log selector is not set, this option has no effect.
+.new
+.option hosts_proxy main "host list&!!" unset
+.cindex proxy "proxy protocol"
+This option enables use of Proxy Protocol proxies for incoming
+connections. For details see &<<SECTproxyInbound>>&.
+.wen
+
+
.option hosts_treat_as_local main "domain list&!!" unset
.cindex "local host" "domains treated as"
.cindex "host" "treated as local"
@@ -35461,6 +35480,9 @@ selection marked by asterisks:
&` queue_time `& time on queue for one recipient
&` queue_time_overall `& time on queue for whole message
&` pid `& Exim process id
+.new
+&` proxy `& proxy address on <= lines
+.wen
&` received_recipients `& recipients on <= lines
&` received_sender `& sender on <= lines
&`*rejected_header `& header contents on reject log
@@ -35587,6 +35609,16 @@ rejection lines, and (despite the name) to outgoing &"=>"& and &"->"& lines.
The latter can be disabled by turning off the &%outgoing_interface%& option.
.wen
.next
+.new
+.cindex log "incoming proxy address"
+.cindex proxy "logging proxy address"
+.cindex "TCP/IP" "logging proxy address"
+&%proxy%&: The internal (closest to the system running Exim) IP address
+of the proxy, tagged by PRX=, on the &"<="& line for a message accepted
+on a proxied connection.
+See &<<SECTproxyInbound>>& for more information.
+.wen
+.next
.cindex "log" "incoming remote port"
.cindex "port" "logging remote"
.cindex "TCP/IP" "logging incoming remote port"
@@ -38025,6 +38057,74 @@ for more information of what they mean.
A proxy is an intermediate system through which communication is passed.
Proxies may provide a security, availability or load-distribution function.
+
+.section "Inbound proxies" SECTproxyInbound
+.cindex proxy inbound
+.cindex proxy "server side"
+.cindex proxy "Proxy protocol"
+.cindex "Proxy protocol" proxy
+
+Exim has support for receiving inbound SMTP connections via a proxy
+that uses &"Proxy Protocol"& to speak to it.
+To include this support, include &"SUPPORT_PROXY=yes"&
+in Local/Makefile.
+
+It was built on specifications from:
+http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt
+That URL was revised in May 2014 to version 2 spec:
+http://git.1wt.eu/web?p=haproxy.git;a=commitdiff;h=afb768340c9d7e50d8e
+
+The purpose of this facility is so that an application load balancer,
+such as HAProxy, can sit in front of several Exim servers
+to distribute load.
+Exim uses the local protocol communication with the proxy to obtain
+the remote SMTP system IP address and port information.
+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).
+
+Use of a proxy is enabled by setting the &%hosts_proxy%&
+main configuration option to a hostlist; connections from these
+hosts will use Proxy Protocol.
+
+To log the IP of the proxy in the incoming logline, add &"+proxy"&
+to the &%log_selector%& option.
+This will add a component tagged with &"PRX="& to the line.
+
+The following expansion variables are usable
+(&"internal"& and &"external"& here refer to the interfaces
+of the proxy):
+.display
+&'proxy_host_address '& internal IP address of the proxy
+&'proxy_host_port '& internal TCP port of the proxy
+&'proxy_target_address '& external IP address of the proxy
+&'proxy_target_port '& external TCP port of the proxy
+&'proxy_session '& boolean: SMTP connection via proxy
+.endd
+If &$proxy_session$& is set but &$proxy_host_address$& is empty
+there was a protocol error.
+
+Since the real connections are all coming from the 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 option set so high, you lose the ability
+to protect your server from many connections from one IP.
+In order to prevent your server from overload, you
+need to add a per connection ratelimit to your connect ACL.
+A possible solution is:
+.display
+ # 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
+.endd
+
+
+
.section "Outbound proxies" SECTproxySOCKS
.cindex proxy outbound
.cindex proxy "client side"
@@ -38035,7 +38135,8 @@ using a protocol called SOCKS5 (defined by RFC1928).
The support can be optionally included by defining SUPPORT_SOCKS=yes in
Local/Makefile.
-Use of a proxy is enabled by setting the &%socks_proxy%& on an smtp transport.
+Use of a proxy is enabled by setting the &%socks_proxy%& option
+on an smtp transport.
The option value is expanded and should then be a list
(colon-separated by default) of proxy specifiers.
Each proxy specifier is a list
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index d57c3db00..1fa19daad 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -115,6 +115,10 @@ JH/22 Bugs 963, 1721: Fix some corner cases in message body canonicalisation
JH/23 Move SOCKS5 support from Experimental to mainline, enabled for a build
by defining SUPPORT_SOCKS.
+JH/26 Move PROXY support from Experimental to mainline, enabled for a build
+ by defining SUPPORT_PROXY. Note that the proxy_required_hosts option
+ is renamed to hosts_proxy.
+
Exim version 4.86
-----------------
diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index f0f1035ea..45e7d1ba1 100644
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -973,151 +973,6 @@ Where SPAMMER_SET is a macro and it is defined as
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
-
-
-
-
DANE
------------------------------------------------------------
DNS-based Authentication of Named Entities, as applied
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-25 18:57:18 +0000