infra/pastila/smtp.nix
2024-07-01 15:35:10 +02:00

948 lines
No EOL
40 KiB
Nix

{ config, lib, pkgs, ... }:
let
opendkim_selector = "21062024";
exim = pkgs.exim.override {
enableAuthDovecot = true;
};
in
{
services.opendkim = {
enable = true;
selector = opendkim_selector;
domains = "csl:isomorphis.me,tremeg.net,gueneau.me";
configFile = builtins.toFile "dkimconfig" ''
RequireSafeKeys false
'';
};
users.groups."vmail" = {};
users.users."vmail" = {
isSystemUser = true;
group = "vmail";
home = "/var/vmail";
};
users.users."exim".extraGroups = [
config.services.opendkim.group
];
services.exim = {
enable = true;
package = exim;
config = ''
######################################################################
# MAIN CONFIGURATION SETTINGS #
######################################################################
# Specify your host's canonical name here. This should normally be the fully
# qualified "official" name of your host. If this option is not set, the
# uname() function is called to obtain the name. In many cases this does
# the right thing and you need not set anything explicitly.
primary_hostname = pastila.isomorphis.me
# The next three settings create two lists of domains and one list of hosts.
# These lists are referred to later in this configuration using the syntax
# +local_domains, +relay_to_domains, and +relay_from_hosts, respectively. They
# are all colon-separated lists:
domainlist local_domains = @ : isomorphis.me : tremeg.net : gueneau.me : armael.net
domainlist relay_to_domains = polyno.me
hostlist relay_from_hosts = 127.0.0.1
hostlist host_auth_accept_relay = *
# Most straightforward access control requirements can be obtained by
# appropriate settings of the above options. In more complicated situations,
# you may need to modify the Access Control Lists (ACLs) which appear later in
# this file.
# The first setting specifies your local domains, for example:
#
# domainlist local_domains = my.first.domain : my.second.domain
#
# You can use "@" to mean "the name of the local host", as in the default
# setting above. This is the name that is specified by primary_hostname,
# as specified above (or defaulted). If you do not want to do any local
# deliveries, remove the "@" from the setting above. If you want to accept mail
# addressed to your host's literal IP address, for example, mail addressed to
# "user@[192.168.23.44]", you can add "@[]" as an item in the local domains
# list. You also need to uncomment "allow_domain_literals" below. This is not
# recommended for today's Internet.
# The second setting specifies domains for which your host is an incoming relay.
# If you are not doing any relaying, you should leave the list empty. However,
# if your host is an MX backup or gateway of some kind for some domains, you
# must set relay_to_domains to match those domains. For example:
#
# domainlist relay_to_domains = *.myco.com : my.friend.org
#
# This will allow any host to relay through your host to those domains.
# See the section of the manual entitled "Control of relaying" for more
# information.
# The third setting specifies hosts that can use your host as an outgoing relay
# to any other host on the Internet. Such a setting commonly refers to a
# complete local network as well as the localhost. For example:
#
# hostlist relay_from_hosts = 127.0.0.1 : 192.168.0.0/16
#
# The "/16" is a bit mask (CIDR notation), not a number of hosts. Note that you
# have to include 127.0.0.1 if you want to allow processes on your host to send
# SMTP mail by using the loopback address. A number of MUAs use this method of
# sending mail.
# All three of these lists may contain many different kinds of item, including
# wildcarded names, regular expressions, and file lookups. See the reference
# manual for details. The lists above are used in the access control lists for
# checking incoming messages. The names of these ACLs are defined here:
acl_smtp_rcpt = acl_check_rcpt
acl_smtp_data = acl_check_spam
# You should not change those settings until you understand how ACLs work.
# If you are running a version of Exim that was compiled with the content-
# scanning extension, you can cause incoming messages to be automatically
# scanned for viruses. You have to modify the configuration in two places to
# set this up. The first of them is here, where you define the interface to
# your scanner. This example is typical for ClamAV; see the manual for details
# of what to set for other virus scanners. The second modification is in the
# acl_check_data access control list (see below).
# av_scanner = clamd:/tmp/clamd
# For spam scanning, there is a similar option that defines the interface to
# SpamAssassin. You do not need to set this if you are using the default, which
# is shown in this commented example. As for virus scanning, you must also
# modify the acl_check_data access control list to enable spam scanning.
# spamd_address = 127.0.0.1 11333 variant=rspamd
# If Exim is compiled with support for TLS, you may want to enable the
# following options so that Exim allows clients to make encrypted
# connections. In the authenticators section below, there are template
# configurations for plaintext username/password authentication. This kind
# of authentication is only safe when used within a TLS connection, so the
# authenticators will only work if the following TLS settings are turned on
# as well.
# Allow any client to use TLS.
tls_advertise_hosts = *
# Specify the location of the Exim server's TLS certificate and private key.
# The private key must not be encrypted (password protected). You can put
# the certificate and private key in the same file, in which case you only
# need the first setting, or in separate files, in which case you need both
# options.
tls_certificate = ${config.security.acme.certs."smtp".directory + "/cert.pem"}
tls_privatekey = ${config.security.acme.certs."smtp".directory + "/key.pem"}
# (use the defaults as those are most likely outdated)
# openssl_options = +no_sslv2 +no_sslv3
# tls_require_ciphers = HIGH:!DES:!RC4:!MD5
# In order to support roaming users who wish to send email from anywhere,
# you may want to make Exim listen on other ports as well as port 25, in
# case these users need to send email from a network that blocks port 25.
# The standard port for this purpose is port 587, the "message submission"
# port. See RFC 4409 for details. Microsoft MUAs cannot be configured to
# talk the message submission protocol correctly, so if you need to support
# them you should also allow TLS-on-connect on the traditional but
# non-standard port 465.
daemon_smtp_ports = 25 : 465 : 587
tls_on_connect_ports = 465
# Specify the domain you want to be added to all unqualified addresses
# here. An unqualified address is one that does not contain an "@" character
# followed by a domain. For example, "caesar@rome.example" is a fully qualified
# address, but the string "caesar" (i.e. just a login name) is an unqualified
# email address. Unqualified addresses are accepted only from local callers by
# default. See the recipient_unqualified_hosts option if you want to permit
# unqualified addresses from remote sources. If this option is not set, the
# primary_hostname value is used for qualification.
qualify_domain = isomorphis.me
# If you want unqualified recipient addresses to be qualified with a different
# domain to unqualified sender addresses, specify the recipient domain here.
# If this option is not set, the qualify_domain value is used.
# qualify_recipient =
# The following line must be uncommented if you want Exim to recognize
# addresses of the form "user@[10.11.12.13]" that is, with a "domain literal"
# (an IP address) instead of a named domain. The RFCs still require this form,
# but it makes little sense to permit mail to be sent to specific hosts by
# their IP address in the modern Internet. This ancient format has been used
# by those seeking to abuse hosts by using them for unwanted relaying. If you
# really do want to support domain literals, uncomment the following line, and
# see also the "domain_literal" router below.
# allow_domain_literals
# No deliveries will ever be run under the uids of users specified by
# never_users (a colon-separated list). An attempt to do so causes a panic
# error to be logged, and the delivery to be deferred. This is a paranoic
# safety catch. There is an even stronger safety catch in the form of the
# FIXED_NEVER_USERS setting in the configuration for building Exim. The list of
# users that it specifies is built into the binary, and cannot be changed. The
# option below just adds additional users to the list. The default for
# FIXED_NEVER_USERS is "root", but just to be absolutely sure, the default here
# is also "root".
# Note that the default setting means you cannot deliver mail addressed to root
# as if it were a normal user. This isn't usually a problem, as most sites have
# an alias for root that redirects such mail to a human administrator.
never_users = root
# The setting below causes Exim to do a reverse DNS lookup on all incoming
# IP calls, in order to get the true host name. If you feel this is too
# expensive, you can specify the networks for which a lookup is done, or
# remove the setting entirely.
host_lookup = *
# The settings below, which are actually the same as the defaults in the
# code, cause Exim to make RFC 1413 (ident) callbacks for all incoming SMTP
# calls. You can limit the hosts to which these calls are made, and/or change
# the timeout that is used. If you set the timeout to zero, all RFC 1413 calls
# are disabled. RFC 1413 calls are cheap and can provide useful information
# for tracing problem messages, but some hosts and firewalls have problems
# with them. This can result in a timeout instead of an immediate refused
# connection, leading to delays on starting up SMTP sessions. (The default was
# reduced from 30s to 5s for release 4.61.)
rfc1413_hosts =
# rfc1413_query_timeout = 5s
# By default, Exim expects all envelope addresses to be fully qualified, that
# is, they must contain both a local part and a domain. If you want to accept
# unqualified addresses (just a local part) from certain hosts, you can specify
# these hosts by setting one or both of
#
# sender_unqualified_hosts =
# recipient_unqualified_hosts =
#
# to control sender and recipient addresses, respectively. When this is done,
# unqualified addresses are qualified using the settings of qualify_domain
# and/or qualify_recipient (see above).
# If you want Exim to support the "percent hack" for certain domains,
# uncomment the following line and provide a list of domains. The "percent
# hack" is the feature by which mail addressed to x%y@z (where z is one of
# the domains listed) is locally rerouted to x@y and sent on. If z is not one
# of the "percent hack" domains, x%y is treated as an ordinary local part. This
# hack is rarely needed nowadays; you should not enable it unless you are sure
# that you really need it.
#
# percent_hack_domains =
#
# As well as setting this option you will also need to remove the test
# for local parts containing % in the ACL definition below.
# When Exim can neither deliver a message nor return it to sender, it "freezes"
# the delivery error message (aka "bounce message"). There are also other
# circumstances in which messages get frozen. They will stay on the queue for
# ever unless one of the following options is set.
# This option unfreezes frozen bounce messages after two days, tries
# once more to deliver them, and ignores any delivery failures.
ignore_bounce_errors_after = 2d
# This option cancels (removes) frozen messages that are older than a week.
timeout_frozen_after = 7d
# By default, messages that are waiting on Exim's queue are all held in a
# single directory called "input" which it itself within Exim's spool
# directory. (The default spool directory is specified when Exim is built, and
# is often /var/spool/exim/.) Exim works best when its queue is kept short, but
# there are circumstances where this is not always possible. If you uncomment
# the setting below, messages on the queue are held in 62 subdirectories of
# "input" instead of all in the same directory. The subdirectories are called
# 0, 1, ... A, B, ... a, b, ... z. This has two benefits: (1) If your file
# system degrades with many files in one directory, this is less likely to
# happen; (2) Exim can process the queue one subdirectory at a time instead of
# all at once, which can give better performance with large queues.
# split_spool_directory = true
# If you're in a part of the world where ASCII is not sufficient for most
# text, then you're probably familiar with RFC2047 message header extensions.
# By default, Exim adheres to the specification, including a limit of 76
# characters to a line, with encoded words fitting within a line.
# If you wish to use decoded headers in message filters in such a way
# that successful decoding of malformed messages matters, you may wish to
# configure Exim to be more lenient.
#
# check_rfc2047_length = false
#
# In particular, the Exim maintainers have had multiple reports of problems
# from Russian administrators of issues until they disable this check,
# because of some popular, yet buggy, mail composition software.
# If you wish to be strictly RFC compliant, or if you know you'll be
# exchanging email with systems that are not 8-bit clean, then you may
# wish to disable advertising 8BITMIME. Uncomment this option to do so.
# accept_8bitmime = false
slow_lookup_log = 500
log_selector = +ident_timeout
######################################################################
# ACL CONFIGURATION #
# Specifies access control lists for incoming SMTP mail #
######################################################################
begin acl
# .include /etc/mail/acl-greylist-sqlite
# This access control list is used for every RCPT command in an incoming
# SMTP message. The tests are run in order until the address is either
# accepted or denied.
acl_check_rcpt:
# Accept if the source is local SMTP (i.e. not over TCP/IP). We do this by
# testing for an empty sending host field.
accept hosts = :
control = dkim_disable_verify
#############################################################################
# The following section of the ACL is concerned with local parts that contain
# @ or % or ! or / or | or dots in unusual places.
#
# The characters other than dots are rarely found in genuine local parts, but
# are often tried by people looking to circumvent relaying restrictions.
# Therefore, although they are valid in local parts, these rules lock them
# out, as a precaution.
#
# Empty components (two dots in a row) are not valid in RFC 2822, but Exim
# allows them because they have been encountered. (Consider local parts
# constructed as "firstinitial.secondinitial.familyname" when applied to
# someone like me, who has no second initial.) However, a local part starting
# with a dot or containing /../ can cause trouble if it is used as part of a
# file name (e.g. for a mailing list). This is also true for local parts that
# contain slashes. A pipe symbol can also be troublesome if the local part is
# incorporated unthinkingly into a shell command line.
#
# Two different rules are used. The first one is stricter, and is applied to
# messages that are addressed to one of the local domains handled by this
# host. The line "domains = +local_domains" restricts it to domains that are
# defined by the "domainlist local_domains" setting above. The rule blocks
# local parts that begin with a dot or contain @ % ! / or |. If you have
# local accounts that include these characters, you will have to modify this
# rule.
deny message = Restricted characters in address
domains = +local_domains
local_parts = ^[.] : ^.*[@%!/|]
# The second rule applies to all other domains, and is less strict. The line
# "domains = !+local_domains" restricts it to domains that are NOT defined by
# the "domainlist local_domains" setting above. The exclamation mark is a
# negating operator. This rule allows your own users to send outgoing
# messages to sites that use slashes and vertical bars in their local parts.
# It blocks local parts that begin with a dot, slash, or vertical bar, but
# allows these characters within the local part. However, the sequence /../
# is barred. The use of @ % and ! is blocked, as before. The motivation here
# is to prevent your users (or your users' viruses) from mounting certain
# kinds of attack on remote sites.
deny message = Restricted characters in address
domains = !+local_domains
local_parts = ^[./|] : ^.*[@%!] : ^.*/\\.\\./
#############################################################################
# Accept mail to postmaster in any local domain, regardless of the source,
# and without verifying the sender.
accept local_parts = postmaster
domains = +local_domains
# Deny unless the sender address can be verified.
require verify = sender
# Accept if the message comes from one of the hosts for which we are an
# outgoing relay. It is assumed that such hosts are most likely to be MUAs,
# so we set control=submission to make Exim treat the message as a
# submission. It will fix up various errors in the message, for example, the
# lack of a Date: header line. If you are actually relaying out out from
# MTAs, you may want to disable this. If you are handling both relaying from
# MTAs and submissions from MUAs you should probably split them into two
# lists, and handle them differently.
# Recipient verification is omitted here, because in many cases the clients
# are dumb MUAs that don't cope well with SMTP error responses. If you are
# actually relaying out from MTAs, you should probably add recipient
# verification here.
# Note that, by putting this test before any DNS black list checks, you will
# always accept from these hosts, even if they end up on a black list. The
# assumption is that they are your friends, and if they get onto a black
# list, it is a mistake.
accept hosts = +relay_from_hosts
control = submission
control = dkim_disable_verify
# Accept if the message arrived over an authenticated connection, from
# any host. Again, these messages are usually from MUAs, so recipient
# verification is omitted, and submission mode is set. And again, we do this
# check before any black list tests.
accept authenticated = *
control = submission/sender_retain
control = dkim_disable_verify
# Insist that any other recipient address that we accept is either in one of
# our local domains, or is in a domain for which we explicitly allow
# relaying. Any other domain is rejected as being unacceptable for relaying.
require message = relay not permitted
domains = +local_domains : +relay_to_domains
# We also require all accepted addresses to be verifiable. This check will
# do local part verification for local domains, but only check the domain
# for remote domains. The only way to check local parts for the remote
# relay domains is to use a callout (add /callout), but please read the
# documentation about callouts before doing this.
require verify = recipient
#############################################################################
# There are no default checks on DNS black lists because the domains that
# contain these lists are changing all the time. However, here are two
# examples of how you can get Exim to perform a DNS black list lookup at this
# point. The first one denies, whereas the second just warns.
#
# deny message = rejected because $sender_host_address is in a black list at $dnslist_domain\n$dnslist_text
# dnslists = black.list.example
#
# warn dnslists = black.list.example
# add_header = X-Warning: $sender_host_address is in a black list at $dnslist_domain
# log_message = found in $dnslist_domain
#############################################################################
#############################################################################
# This check is commented out because it is recognized that not every
# sysadmin will want to do it. If you enable it, the check performs
# Client SMTP Authorization (csa) checks on the sending host. These checks
# do DNS lookups for SRV records. The CSA proposal is currently (May 2005)
# an Internet draft. You can, of course, add additional conditions to this
# ACL statement to restrict the CSA checks to certain hosts only.
#
# require verify = csa
#############################################################################
# At this point, the address has passed all the checks that have been
# configured, so we accept it unconditionally.
accept
# This ACL is used after the contents of a message have been received. This
# is the ACL in which you can test a message's headers or body, and in
# particular, this is where you can invoke external virus or spam scanners.
# Some suggested ways of configuring these tests are shown below, commented
# out. Without any tests, this ACL accepts all messages. If you want to use
# such tests, you must ensure that Exim is compiled with the content-scanning
# extension (WITH_CONTENT_SCAN=yes in Local/Makefile).
acl_check_data:
# warn message = X-MIME-Error: $demime_reason
# demime = *
# condition = ''${if >{$demime_errorlevel}{0}{1}{0}}
# set acl_m_greylistreasons = Message has MIME error: $demime_reason\n$acl_m_greylistreasons
# warn condition = ''${if and { \
# {match {''${lc:$h_subject:}}{^re:}} \
# {!def:h_References:} \
# {!def:h_In-Reply-To:} \
# } {1}{0}}
# message = X-Bad-Reply: 'Re:' in Subject but no References or In-Reply-To headers
# set acl_m_greylistreasons = Message has 'Re:' in Subject: but neither References: nor In-Reply-To:\n$acl_m_greylistreasons
# warn condition = ''${if !def:h_Message-ID: {1}}
# set acl_m_greylistreasons = Message has no Message-Id: header\n$acl_m_greylistreasons
# warn dnslists = psbl.surriel.org
# set acl_m_greylistreasons = Host listed in $dnslist_domain blacklist: $dnslist_text\n$acl_m_greylistreasons
# require acl = greylist_mail
# Deny if the message contains a virus. Before enabling this check, you
# must install a virus scanner and set the av_scanner option above.
#
# deny malware = *
# message = This message contains a virus ($malware_name).
# Add headers to a message if it is judged to be spam. Before enabling this,
# you must install SpamAssassin. You may also need to set the spamd_address
# option above.
#
# warn spam = nobody
# add_header = X-Spam_score: $spam_score\n\
# X-Spam_score_int: $spam_score_int\n\
# X-Spam_bar: $spam_bar\n\
# X-Spam_report: $spam_report
# Accept the message.
accept
acl_check_spam:
# do not scan messages submitted from our own hosts
# +relay_from_hosts is assumed to be a list of hosts in configuration
accept hosts = +relay_from_hosts
# do not scan messages from submission port (or maybe you want to?)
accept condition = ''${if eq{$interface_port}{587}}
# skip scanning for authenticated users (if desired?)
accept authenticated = *
# add spam-score and spam-report header when told by rspamd
warn spam = nobody:true
condition = ''${if eq{$spam_action}{add header}}
add_header = X-Spam-Score: $spam_score ($spam_bar)
add_header = X-Spam-Report: $spam_report
# $spam_action is the action recommended by rspamd
# $spam_score is the message score (we unlikely need it)
# $spam_score_int is spam score multiplied by 10
# $spam_report lists symbols matched & protocol messages
# $spam_bar is a visual indicator of spam/ham level
# use greylisting available in rspamd v1.3+
defer message = Please try again later
condition = ''${if eq{$spam_action}{soft reject}}
deny message = Message discarded as high-probability spam
condition = ''${if eq{$spam_action}{reject}}
accept
######################################################################
# ROUTERS CONFIGURATION #
# Specifies how addresses are handled #
######################################################################
# THE ORDER IN WHICH THE ROUTERS ARE DEFINED IS IMPORTANT! #
# An address is passed to each router in turn until it is accepted. #
######################################################################
begin routers
# This router routes to remote hosts over SMTP by explicit IP address,
# when an email address is given in "domain literal" form, for example,
# <user@[192.168.35.64]>. The RFCs require this facility. However, it is
# little-known these days, and has been exploited by evil people seeking
# to abuse SMTP relays. Consequently it is commented out in the default
# configuration. If you uncomment this router, you also need to uncomment
# allow_domain_literals above, so that Exim can recognize the syntax of
# domain literal addresses.
# domain_literal:
# driver = ipliteral
# domains = ! +local_domains
# transport = remote_smtp
# This router routes addresses that are not in local domains by doing a DNS
# lookup on the domain name. The exclamation mark that appears in "domains = !
# +local_domains" is a negating operator, that is, it can be read as "not". The
# recipient's domain must not be one of those defined by "domainlist
# local_domains" above for this router to be used.
#
# If the router is used, any domain that resolves to 0.0.0.0 or to a loopback
# interface address (127.0.0.0/8) is treated as if it had no DNS entry. Note
# that 0.0.0.0 is the same as 0.0.0.0/32, which is commonly treated as the
# local host inside the network stack. It is not 0.0.0.0/0, the default route.
# If the DNS lookup fails, no further routers are tried because of the no_more
# setting, and consequently the address is unrouteable.
dnslookup:
driver = dnslookup
domains = ! +local_domains
transport = remote_smtp
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
# The remaining routers handle addresses in the local domain(s), that is those
# domains that are defined by "domainlist local_domains" above.
# This router handles aliasing using a linearly searched alias file with the
# name /etc/mail/aliases. When this configuration is installed automatically,
# the name gets inserted into this file from whatever is set in Exim's
# build-time configuration. The default path is the traditional /etc/mail/aliases.
# If you install this configuration by hand, you need to specify the correct
# path in the "data" setting below.
#
##### NB You must ensure that the alias file exists. It used to be the case
##### NB that every Unix had that file, because it was the Sendmail default.
##### NB These days, there are systems that don't have it. Your aliases
##### NB file should at least contain an alias for "postmaster".
#
# If any of your aliases expand to pipes or files, you will need to set
# up a user and a group for these deliveries to run under. You can do
# this by uncommenting the "user" option below (changing the user name
# as appropriate) and adding a "group" option if necessary. Alternatively, you
# can specify "user" on the transports that are used. Note that the transports
# listed below are the same as are used for .forward files; you might want
# to set up different ones for pipe and file deliveries from aliases.
system_aliases:
driver = redirect
allow_fail
allow_defer
data = ''${lookup{$local_part}lsearch{/etc/secrets/exim/aliases}}
# user = exim
file_transport = address_file
pipe_transport = address_pipe
# This router handles forwarding using traditional .forward files in users'
# home directories. If you want it also to allow mail filtering when a forward
# file starts with the string "# Exim filter" or "# Sieve filter", uncomment
# the "allow_filter" option.
# The no_verify setting means that this router is skipped when Exim is
# verifying addresses. Similarly, no_expn means that this router is skipped if
# Exim is processing an EXPN command.
# If you want this router to treat local parts with suffixes introduced by "-"
# or "+" characters as if the suffixes did not exist, uncomment the two local_
# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated
# in the same way as xxxx@your.domain by this router. Because this router is
# not used for verification, if you choose to uncomment those options, then you
# will *need* to make the same change to the localuser router. (There are
# other approaches, if this is undesirable, but they add complexity).
# The check_ancestor option means that if the forward file generates an
# address that is an ancestor of the current one, the current one gets
# passed on instead. This covers the case where A is aliased to B and B
# has a .forward file pointing to A.
# The three transports specified at the end are those that are used when
# forwarding generates a direct delivery to a file, or to a pipe, or sets
# up an auto-reply, respectively.
# userforward:
# driver = redirect
# check_local_user
# # local_part_suffix = +* : -*
# # local_part_suffix_optional
# file = $home/.forward
# # allow_filter
# no_verify
# no_expn
# check_ancestor
# file_transport = address_file
# pipe_transport = address_pipe
# reply_transport = address_reply
# Virtual users/domains
virtual:
driver = redirect
domains = dsearch;/etc/secrets/exim/virtual
# data = ''${lookup{$local_part}wildlsearch{/etc/secrets/exim/virtual/$domain}}
data = ''${lookup{$local_part}wildlsearch{/etc/secrets/exim/virtual/''${lookup{$domain}lsearch{/etc/secrets/exim/domains/domains}}}}
my_domains:
driver = accept
domains = dsearch;/etc/secrets/exim/domains
# local_parts = lsearch;/etc/secrets/exim/domains/$domain
local_parts = lsearch;/etc/secrets/exim/domains/''${lookup{$domain}lsearch{/etc/secrets/exim/domains/domains}}
transport = my_mailboxes
# This router matches local user mailboxes. If the router fails, the error
# message is "Unknown user".
# If you want this router to treat local parts with suffixes introduced by "-"
# or "+" characters as if the suffixes did not exist, uncomment the two local_
# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated
# in the same way as xxxx@your.domain by this router.
localuser:
driver = accept
check_local_user
# local_part_suffix = +* : -*
# local_part_suffix_optional
transport = local_delivery
cannot_route_message = Unknown user
######################################################################
# TRANSPORTS CONFIGURATION #
######################################################################
# ORDER DOES NOT MATTER #
# Only one appropriate transport is called for each delivery. #
######################################################################
# A transport is used only when referenced from a router that successfully
# handles an address.
begin transports
# This transport is used for delivering messages over SMTP connections.
remote_smtp:
driver = smtp
# hosts_require_tls = *
dkim_domain = $sender_address_domain
dkim_selector = ${opendkim_selector}
dkim_private_key = /var/lib/opendkim/keys/${opendkim_selector}.private
dkim_canon = relaxed
dkim_strict = 0
headers_add = X-Clacks-Overhead: "GNU Terry Pratchett"
# This transport is used for local delivery to user mailboxes in traditional
# BSD mailbox format. By default it will be run under the uid and gid of the
# local user, and requires the sticky bit to be set on the /var/mail directory.
# Some systems use the alternative approach of running mail deliveries under a
# particular group instead of using the sticky bit. The commented options below
# show how this can be done.
# local_delivery:
# driver = appendfile
# file = /var/mail/$local_part
# delivery_date_add
# envelope_to_add
# return_path_add
# # group = mail
# # mode = 0660
# This transport is used for handling pipe deliveries generated by alias or
# .forward files. If the pipe generates any standard output, it is returned
# to the sender of the message as a delivery error. Set return_fail_output
# instead of return_output if you want this to happen only when the pipe fails
# to complete normally. You can set different transports for aliases and
# forwards if you want to - see the references to address_pipe in the routers
# section above.
address_pipe:
driver = pipe
return_output
# This transport is used for handling deliveries directly to files that are
# generated by aliasing or forwarding.
address_file:
driver = appendfile
delivery_date_add
envelope_to_add
return_path_add
# This transport is used for handling autoreplies generated by the filtering
# option of the userforward router.
address_reply:
driver = autoreply
# Virtual users/domains
my_mailboxes:
driver = appendfile
maildir_format = true
mode_fail_narrower = false
envelope_to_add = true
return_path_add = true
mode = 0600
# directory = /var/vmail/''${lookup{$domain}lsearch{/etc/secrets/exim/domains/domains}}/$local_part/Maildir
directory = /var/vmail/$domain_data/''${lookup{$local_part}dsearch{/var/vmail/$domain_data}}/Maildir
create_directory = true
user = vmail
######################################################################
# RETRY CONFIGURATION #
######################################################################
begin retry
# This single retry rule applies to all domains and all errors. It specifies
# retries every 15 minutes for 2 hours, then increasing retry intervals,
# starting at 1 hour and increasing each time by a factor of 1.5, up to 16
# hours, then retries every 6 hours until 4 days have passed since the first
# failed delivery.
# WARNING: If you do not have any retry rules at all (this section of the
# configuration is non-existent or empty), Exim will not do any retries of
# messages that fail to get delivered at the first attempt. The effect will
# be to treat temporary errors as permanent. Therefore, DO NOT remove this
# retry rule unless you really don't want any retries.
# Address or Domain Error Retries
# ----------------- ----- -------
* * F,2h,15m; G,16h,1h,1.5; F,4d,6h
######################################################################
# REWRITE CONFIGURATION #
######################################################################
# There are no rewriting specifications in this default configuration file.
begin rewrite
######################################################################
# AUTHENTICATION CONFIGURATION #
######################################################################
# The following authenticators support plaintext username/password
# authentication using the standard PLAIN mechanism and the traditional
# but non-standard LOGIN mechanism, with Exim acting as the server.
# PLAIN and LOGIN are enough to support most MUA software.
#
# These authenticators are not complete: you need to change the
# server_condition settings to specify how passwords are verified.
# They are set up to offer authentication to the client only if the
# connection is encrypted with TLS, so you also need to add support
# for TLS. See the global configuration options section at the start
# of this file for more about TLS.
#
# The default RCPT ACL checks for successful authentication, and will accept
# messages from authenticated users from anywhere on the Internet.
begin authenticators
# PLAIN authentication has no server prompts. The client sends its
# credentials in one lump, containing an authorization ID (which we do not
# use), an authentication ID, and a password. The latter two appear as
# $auth2 and $auth3 in the configuration and should be checked against a
# valid username and password. In a real configuration you would typically
# use $auth2 as a lookup key, and compare $auth3 against the result of the
# lookup, perhaps using the crypteq{}{} condition.
#PLAIN:
# driver = plaintext
# server_set_id = $auth2
# server_prompts = :
# server_condition = Authentication is not yet configured
# server_advertise_condition = ''${if def:tls_cipher }
# plain:
# driver = plaintext
# public_name = PLAIN
# server_advertise_condition = ''${if eq{$tls_cipher}{}{false}{true}}
# server_prompts = :
# server_set_id = $auth2
# server_condition = \
# ''${lookup{$2}wildlsearch{/etc/mail/passwd}\
# {''${if crypteq{$3}{\{sha1\}''${extract{1}{:}{$value}{$value}fail}}\
# {yes}{no}}\
# }\
# }
# LOGIN authentication has traditional prompts and responses. There is no
# authorization ID in this mechanism, so unlike PLAIN the username and
# password are $auth1 and $auth2. Apart from that you can use the same
# server_condition setting for both authenticators.
#LOGIN:
# driver = plaintext
# server_set_id = $auth1
# server_prompts = <| Username: | Password:
# server_condition = Authentication is not yet configured
# server_advertise_condition = ''${if def:tls_cipher }
# login:
# driver = plaintext
# public_name = LOGIN
# server_advertise_condition = ''${if eq{$tls_cipher}{}{false}{true}}
# server_prompts = Username:: : Password::
# server_set_id = $auth1
# server_condition = \
# ''${lookup{$1}wildlsearch{/etc/mail/passwd}\
# {''${if crypteq{$2}{\{sha1\}''${extract{1}{:}{$value}{$value}fail}}\
# {yes}{no}}\
# }\
# }
dovecot_plain:
driver = dovecot
public_name = PLAIN
server_socket = /var/run/dovecot2/auth-client
server_set_id = $auth2
######################################################################
# CONFIGURATION FOR local_scan() #
######################################################################
# If you have built Exim to include a local_scan() function that contains
# tables for private options, you can define those options here. Remember to
# uncomment the "begin" line. It is commented by default because it provokes
# an error with Exim binaries that are not built with LOCAL_SCAN_HAS_OPTIONS
# set in the Local/Makefile.
# begin local_scan
# End of exim configuration.
'';
};
security.acme.certs."smtp" = {
domain = "smtp.isomorphis.me";
extraDomainNames = [
"smtp.tremeg.net"
"smtp.gueneau.me"
];
group = config.services.exim.group;
};
environment.systemPackages = [ pkgs.acl ];
custom.secrets.extraCommands = ''
mkdir -p /etc/secrets/exim/virtual
mkdir -p /etc/secrets/exim/domains
chmod 700 /etc/secrets/exim
chmod 700 /etc/secrets/exim/virtual
chmod 700 /etc/secrets/exim/domains
chown --recursive ${config.services.exim.user}:${config.services.exim.group} /etc/secrets/exim
mkdir -p /etc/secrets/dovecot
chmod -R 700 /etc/secrets/dovecot
chown --recursive ${config.services.dovecot2.user}:${config.services.dovecot2.group} /etc/secrets/dovecot
# XXX clean this up
chmod g+r /var/lib/opendkim/keys/${opendkim_selector}.private
chmod g+rx /var/lib/opendkim/
${pkgs.acl}/bin/setfacl -m g:exim:x /var/lib/opendkim/
${pkgs.acl}/bin/setfacl -m g:exim:x /var/lib/opendkim/keys/
${pkgs.acl}/bin/setfacl -m g:exim:r /var/lib/opendkim/keys/21062024.private
'';
}