eximconf: log information about MIME parts
[mirror/dsa-puppet.git] / modules / exim / templates / eximconf.erb
index d7648fc..a11e8d5 100644 (file)
@@ -8,39 +8,46 @@
 
 # The configuration file uses a set of rules to generate an
 # acceptable mail environment for debian.org machines. It deviates
-# considerably from what could be considered a standard exim configuration.
+# considerably from what could be considered a standard Exim configuration.
 
 # This configuration file brings in the necessary information from
-# other databases stored in /etc/exim/ and the files distributed by ud-ldap
+# other databases stored in /etc/exim4/ and the files distributed by ud-ldap
 
 # This file is independent of the local host, it should not be changed
 # per machine. primary_hostname is used in all places that require per-host 
 # settings.
 
-# The configuration files in /etc/exim are as follows:
+# The configuration files in /etc/exim4 are as follows:
 #  locals - This is a list of domains that are considered local. A local
-#           domain is essential one that deliveries to /var/mail
+#           domain is essentially one for which deliveries to /var/mail
 #           will be attempted. The users available for local delivery
-#           comes from /etc/passwd and /etc/aliases. Wildcards are not
+#           come from /etc/passwd and /etc/aliases. Wildcards are not
 #           permitted.
 #  virtualdomains - This is a list of all virtual domains. A virtual domain
 #           is much like a local domain, execpt that the delivery location
 #           and allowed set of users is controlled by a virtual domain
 #           alias file and not /etc/passwd. Wildcards are permitted
 #  relayhosts - Hostnames that can send any arbitarily addressed mail to
-#           us. This is primarily only usefull for emergancy 'queue
+#           us. This is primarily only useful for emergency 'queue
 #           flushing' operations, but should be populated with a list
 #           of trusted machines. Wildcards are not permitted
 #  bsmtp_domains - Domains that we deliver locally via bsmtp
+#  submission-domains - Domains for which mail will be accepted via the
+#           submission port
 <%- if @is_mailrelay -%>
 #  mailhubdomains - Domains for which we are the MX, but the mail is relayed
 #           elsewhere.  This is designed for use with small volume or
 #           restricted machines that need to use a smarthost for mail
 #           traffic.  We will relay for them based on ssl cert validation
-#           but we need to teach exim how to route the mail to them.  This is
+#           but we need to teach Exim how to route the mail to them.  This is
 #           that list.
 <%- end -%>
 
+# From /var/lib/misc / UD:
+#
+# mail-forward.cdb - aliases for @d.o
+# user-forward.cdb - aliases for @thishost.d.o
+
 # Exim's wildcard mechanism is a bit odd in that to say "any address in
 # debian.org including debian.org" you must use two patterns,
 #   *.debian.org
@@ -50,9 +57,9 @@
 
 # Further details can be found in each of the files.
 
-# Usefull exim commands:
+# Useful Exim commands:
 #  exim4 -qf  - Try sending all messages right now, including frozen ones
-#  exim4 -bt foo@blah - Write what exim would do if it saw the address
+#  exim4 -bt foo@blah - Write what Exim would do if it saw the address
 #                      Great for testing virtual domains and forward files
 
 # Special Features for users:
@@ -68,7 +75,7 @@
 
 # Heuristic check (none bad enough to cause a hard reject, but in aggregate
 # will trigger things like rcpt to rate limiting or possibly a reject if
-# enough hits are triggered.
+# enough hits are triggered).
 #
 # value is stored in acl_c_scr
 
@@ -121,10 +128,16 @@ localpartlist local_only_users = lsearch;/etc/exim4/localusers
 
 localpartlist postmasterish = postmaster : abuse : hostmaster
 
-hostlist debianhosts = <; ; 127.0.0.1 ; ::1 ; /var/lib/misc/thishost/debianhosts ; 89.16.166.49 ; 82.195.75.76 ; 2001:41b8:202:deb:bab5:0:52c3:4b4c
+hostlist debianhosts = <; ; 127.0.0.1 ; ::1 ; /var/lib/misc/thishost/debianhosts
 
 hostlist reservedaddrs = 0.0.0.0/8 : 127.0.0.0/8 : 10.0.0.0/8 : 169.254.0.0/16 : 172.16.0.0/12 : 192.0.0.0/24 : 192.168.0.0/16 : 224.0.0.0/4 : 240.0.0.0/5 : 248.0.0.0/5
 
+domainlist google_mxen = aspmx.l.google.com : gmail-smtp-in.l.google.com : \
+                         *.aspmx.l.google.com : *.gmail-smtp-in.l.google.com
+
+domainlist single_domain_mx = +google_mxen
+domainlist ipv4_only_domain_mx = +google_mxen
+
 <%- if @is_mailrelay -%>
 # Domains we relay for; that is domains that aren't considered local but we 
 # accept mail for them.
@@ -142,7 +155,6 @@ tls_crl = /etc/exim4/ssl/ca.crl
 # expensive, you can specify the networks for which a lookup is done, or
 # remove the setting entirely.
 host_lookup = *
-# dns_ipv4_lookup = !localhost (disabled upon sgrans request, zobel, 2010-03-16)
 
 # If this option is set, then any process that is running as one of the
 # listed users may pass a message to Exim and specify the sender's
@@ -159,14 +171,21 @@ local_from_check = false
 # Some operating systems use the "gecos" field in the system password file
 # to hold other information in addition to users' real names. Exim looks up
 # this field when it is creating "sender" and "from" headers. If these options
-# are set, exim uses "gecos_pattern" to parse the gecos field, and then
+# are set, Exim uses "gecos_pattern" to parse the gecos field, and then
 # expands "gecos_name" as the user's name. $1 etc refer to sub-fields matched
 # by the pattern.
 
 gecos_pattern = ^([^,:]*)
 gecos_name = $1
 
-# This tells exim to immediately discard error messages (ie double bounces).
+# Do *not* include the body of the original message in a bounce
+# The combination of bounce_return_message and bounce_return_body
+# allows us to return only the headers within a bounce
+
+bounce_return_message = true
+bounce_return_body    = false
+
+# This tells Exim to immediately discard error messages (ie double bounces).
 ignore_bounce_errors_after = 0s
 auto_thaw = 1d
 timeout_frozen_after=14d
@@ -219,15 +238,14 @@ av_scanner = clamd:/var/run/clamav/clamd.ctl
 ports = []
 out = "daemon_smtp_ports = "
 ports << 25
+if @mail_port  # if we have an overridden mail_port
+  ports << @mail_port
+end
 
 if @is_bugsmx
   ports << 587
 end
 
-if not scope.lookupvar('deprecated::nodeinfo')['mail_port'].to_s.empty?
-  ports << scope.lookupvar('deprecated::nodeinfo')['mail_port']
-end
-
 if @is_mailrelay
   ports << @smarthost_port
 end
@@ -243,7 +261,23 @@ pipelining_advertise_hosts = !*
 tls_advertise_hosts = *
 smtp_enforce_sync = true
 
-log_selector = +tls_cipher +tls_peerdn +queue_time +deliver_time +smtp_connection +smtp_incomplete_transaction +smtp_confirmation +smtp_protocol_error
+log_selector = \
+               +tls_cipher \
+               +tls_peerdn \
+               +queue_time \
+               +queue_time_overall \
+               +deliver_time \
+               +received_recipients \
+               +sender_on_delivery \
+               +return_path_on_delivery \
+               +incoming_port \
+               +unknown_in_list \
+               +smtp_connection \
+               +smtp_incomplete_transaction \
+               +smtp_confirmation \
+               +smtp_syntax_error \
+               +smtp_no_mail \
+               +smtp_protocol_error
 
 received_header_text = Received: ${if def:sender_rcvhost {from $sender_rcvhost\n\t}\
                                  {${if def:sender_ident {from ${quote_local_part:$sender_ident} }}${if def:sender_helo_name {(helo=$sender_helo_name)\n\t}}}}\
@@ -255,6 +289,7 @@ received_header_text = Received: ${if def:sender_rcvhost {from $sender_rcvhost\n
 
 # macro definitions.
 # Do not wrap!
+MAX_SCAN_SIZE = 256000
 VDOMAINDATA = ${lookup{$domain}partial-lsearch{/etc/exim4/virtualdomains}{$value}}
 VSENDERDOMAINDATA = ${lookup{$sender_address_domain}partial-lsearch{/etc/exim4/virtualdomains}{$value}}
 WHITELIST = ${if match_domain{$domain}{+virtual_domains}\
@@ -268,6 +303,12 @@ GREYLIST_LOCAL_PARTS = ${if match_domain{$domain}{+virtual_domains}\
                        {${lookup{$local_part}lsearch{/etc/exim4/grey_users}{$local_part}{}}}} : \
                        ${lookup{$local_part}lsearch{/var/lib/misc/$primary_hostname/mail-greylist}{$local_part}{}}
 <%- if @is_rtmaster -%>
+# This subject rewrite is embedded in double-quoted strings. As such, some of
+# the items need more escaping than usual, otherwise \N becomes simply "N" and
+# the following "\[" a literal "[".
+# Note that the lack of space in "Subject:${" is intentional, as the raw Subject
+# header will include the leading space, if present.
+RT_SUBJECT = Subject:${if and {{first_delivery}{match {${sg {$rh_Subject:}{\\n([ \\t])}{ }}}{\\N(?i)(.*?)\\[?debian rt\\]?[:\\t ]*(.*)\\N}}}{$1$2}{$h_subject:}}
 RT_QUEUE_MAP = /srv/rt.debian.org/mail/rt_queue_map
 <%- end -%>
 
@@ -288,15 +329,16 @@ acl_spamlovers:
   deny
 
 acl_getprofile:
-  # This is a bad hack to reset the variable, by defining it be something
-  # never referenced.
 
-  warn    set acl_m_rprf = $acl_m_undefined
+  # Determine the mail profile for this recipient.
+  # An empty string implies no match has been found.
+
+  warn    set acl_m_rprf = 
 
   warn    recipients     = survey@popcon.debian.org
           set acl_m_rprf = PopconMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    local_parts    = +local_only_users
           domains        = +local_domains
@@ -310,92 +352,92 @@ acl_getprofile:
           set acl_m_rprf = localonly
 
 <%- end -%>
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
 <%- if @is_rtmaster -%>
   warn    domains        = rt.debian.org
           set acl_m_rprf = RTMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
 <%- end -%>
 <%- if @is_bugsmx -%>
   warn    domains        = bugs.debian.org
           set acl_m_rprf = BugsMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
 <%- end -%>
 <%- if @is_packagesmaster -%>
   warn    domains        = packages.debian.org
           set acl_m_rprf = PackagesMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
 <%- end -%>
 <%- if @is_packagesqamaster -%>
   warn    recipients     = owner@packages.qa.debian.org : postmaster@packages.qa.debian.org
           set acl_m_rprf = PTSOwner
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    senders        = :
           domains        = packages.qa.debian.org
           condition      = ${if match{$local_part}{\N^bounces+\N}}
           set acl_m_rprf = PTSListBounce
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = packages.qa.debian.org
           set acl_m_rprf = PTSMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
 <%- end -%>
   warn    recipients     = change@db.debian.org : changes@db.debian.org : chpasswd@db.debian.org : ping@db.debian.org : recommend@nm.debian.org
           set acl_m_rprf = DBSignedMail
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +virtual_domains
           condition      = ${if exists {${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction}}}}
           condition      = ${if eq{${lookup{$local_part}lsearch*{${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction}}}{$value}{}}}{markup}}
           set acl_m_rprf = markup
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +virtual_domains
           condition      = ${if exists {${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction}}}}
           condition      = ${if eq{${lookup{$local_part}lsearch*{${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction}}}{$value}{}}}{blackhole}}
           set acl_m_rprf = blackhole
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +virtual_domains
           condition      = ${if exists {${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction.cdb}}}}
           condition      = ${if eq{${lookup{$local_part}cdb{${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction.cdb}}}{$value}{}}}{markup}}
           set acl_m_rprf = markup
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +virtual_domains
           condition      = ${if exists {${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction.cdb}}}}
           condition      = ${if eq{${lookup{$local_part}cdb{${extract{directory}{VDOMAINDATA}{${value}/contentinspectionaction.cdb}}}{$value}{}}}{blackhole}}
           set acl_m_rprf = blackhole
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +local_domains
           condition      = ${if eq{${lookup{$local_part}cdb{/var/lib/misc/${primary_hostname}/mail-contentinspectionaction.cdb}{$value}{}}}{markup}}
           set acl_m_rprf = markup
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    domains        = +local_domains
           condition      = ${if eq{${lookup{$local_part}cdb{/var/lib/misc/${primary_hostname}/mail-contentinspectionaction.cdb}{$value}{}}}{blackhole}}
           set acl_m_rprf = blackhole
 
-  accept  condition      = ${if eq {$acl_m_rprf}{}{no}{yes}}
+  accept  condition      = ${if !eq {$acl_m_rprf}{}}
 
   warn    set acl_m_rprf = normal
 
@@ -413,19 +455,22 @@ check_helo:
   # These are in HELO acl so that they are only run once.  They increment a counter,
   # so we don't want it to increment per rcpt to.
 
+  # high trust
   warn    dnslists       = list.dnswl.org&0.0.0.3
           log_message    = Hit on list.dnswl.org for $sender_host_address
           set acl_c_scr  = ${eval:$acl_c_scr-30}
 
+  # >= medium trust
   warn    dnslists       = list.dnswl.org&0.0.0.2
           log_message    = Hit on list.dnswl.org for $sender_host_address
           set acl_c_scr  = ${eval:$acl_c_scr-20}
 
+  # any form of listing
   warn    dnslists       = list.dnswl.org
           log_message    = Hit on list.dnswl.org for $sender_host_address
           set acl_c_scr  = ${eval:$acl_c_scr-10}
 
-  warn    condition      = ${if isip {$sender_helo_name}{true}{false}}
+  warn    condition      = ${if isip {$sender_helo_name}}
           log_message    = remote host used IP address in HELO/EHLO greeting
           set acl_c_scr  = ${eval:$acl_c_scr+20}
 
@@ -433,15 +478,18 @@ check_helo:
           condition      = ${if eq{$host_lookup_failed}{1}}
           set acl_c_scr  = ${eval:$acl_c_scr+20}
 
+  # HELO looks like a dynamic address (with RDNS match)
   warn    !hosts         = +debianhosts
           condition      = ${if eq{$host_lookup_failed}{0}}
           condition      = ${if match{$sender_host_name}{\N(^[^\.]*[0-9]\-+[0-9]|^[^\.]*[0-9]{5,}[^\.]|^([^\.]+\.)?[0-9][^ \.]*\.[^\.]+\..+\.[a-z]|^[^\.]*[0-9]\.[^\.]*[0-9]-[0-9]|^(dyn|cable|dhcp|dialup|ppp|adsl)[^\.]*[0-9])\N}}
           set acl_c_scr  = ${eval:$acl_c_scr+20}
 
+  # HELO looks like a dynamic address
   warn    !hosts         = +debianhosts
           condition      = ${if match{$sender_helo_name}{\N(^[^\.]*[0-9]\-+[0-9]|^[^\.]*[0-9]{5,}[^\.]|^([^\.]+\.)?[0-9][^ \.]*\.[^\.]+\..+\.[a-z]|^[^\.]*[0-9]\.[^\.]*[0-9]-[0-9]|^(dyn|cable|dhcp|dialup|ppp|adsl)[^\.]*[0-9])\N}}
           set acl_c_scr  = ${eval:$acl_c_scr+20}
 
+  # mail from a dynamic IP address range
   warn    !hosts         = +debianhosts
           dnslists       = dul.dnsbl.sorbs.net
           set acl_c_scr  = ${eval:$acl_c_scr+15}
@@ -452,9 +500,9 @@ check_helo:
   # if rDNS does not match helo name (both lower cased first), greylist.
 
   warn    !hosts         = +debianhosts
-          condition      = ${if eq {$host_lookup_failed}{1}{no}{yes}}
-          condition      = ${if def:sender_helo_name {yes}{no}}
-          condition      = ${if eq {${lc:$sender_helo_name}}{${lc:$sender_host_name}}{no}{yes}}
+          condition      = ${if !eq {$host_lookup_failed}{1}}
+          condition      = ${if def:sender_helo_name}
+          condition      = ${if !eq {${lc:$sender_helo_name}}{${lc:$sender_host_name}}}
           log_message    = HELO doesn't match rDNS
           set acl_c_scr  = ${eval:$acl_c_scr+8}
 
@@ -479,7 +527,7 @@ check_helo:
   # skip matching on machines named .*smtp.*, since that's 4 already.  This is a fairly
   # naive test, so it's not worth much
 
-  warn condition       = ${if match {${lc:$sender_helo_name}}{smtp}{no}{yes}}
+  warn condition       = ${if !match {${lc:$sender_helo_name}}{smtp}}
        condition       = ${if match {${lc:$sender_helo_name}}{\N^[a-z0-9]+\.[a-z]+$\N}}
        condition       = ${if match {${lc:$sender_helo_name}}{\N.*[bcdfghjklmnpqrstvwxz]{7,}.*\.[a-z]+$\N}}
        log_message     = random HELO
@@ -497,8 +545,6 @@ check_helo:
 #!!# ACL that is used after the RCPT command on the submission port
 check_submission:
 
-  # 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 = +debianhosts
 
 <%- if @is_mailrelay -%>
@@ -506,11 +552,11 @@ check_submission:
 
 <%- end -%>
   # Defer after too many bad RCPT TO's.  Legit MTAs will retry later.
-  # This is a rough pass at preventing addres harvesting or other mail blasts.
+  # This is a rough pass at preventing address harvesting or other mail blasts.
 
   defer  log_message   = Too many bad recipients ${eval:$rcpt_fail_count} out of $rcpt_count
          message       = Too many bad recipients, try again later
-         condition     = ${if > {${eval:$rcpt_fail_count}}{3}{yes}{no}}
+         condition     = ${if > {${eval:$rcpt_fail_count}}{3}}
 
   defer
           ratelimit      = 5 / 60m / per_rcpt / $sender_host_address
@@ -546,7 +592,7 @@ check_recipient:
           condition     = ${if eq{$acl_m_prf}{}}
           set acl_m_prf = $acl_m_rprf
 
-  defer   condition     = ${if eq{$acl_m_prf}{$acl_m_rprf}{no}{yes}}
+  defer   condition     = ${if !eq{$acl_m_prf}{$acl_m_rprf}}
           message       = Different profile, please retry
           log_message   = Only one profile at a time, please
 
@@ -557,13 +603,13 @@ check_recipient:
          !acl          = acl_spamlovers
          message       = Too many bad recipients, try again later
          !hosts        = +debianhosts
-         condition     = ${if > {${eval:$rcpt_fail_count}}{3}{yes}{no}}
+         condition     = ${if > {${eval:$rcpt_fail_count}}{3}}
 
   # Dump spambots that are so stupid they say helo as our IP address
 
   drop   !hosts        = +debianhosts
          !acl          = acl_spamlovers
-         condition     = ${if eq {$sender_helo_name}{$interface_address}{yes}{no}}
+         condition     = ${if eq {$sender_helo_name}{$interface_address}}
          message       = HELO mismatch Forged HELO for ($sender_helo_name)
 
   # Also for spambots that say helo as us or one of our domains
@@ -585,16 +631,16 @@ check_recipient:
 
   defer  !hosts        = +debianhosts
          !acl          = acl_spamlovers
-         condition     = ${if eq{$acl_m_frg}{}{no}{yes}}
-         condition     = ${if eq{$sender_host_name}{}{yes}{no}}
-         condition     = ${if eq{$host_lookup_failed}{1}{no}{yes}}
+         condition     = ${if !eq{$acl_m_frg}{}}
+         condition     = ${if eq{$sender_host_name}{}}
+         condition     = ${if !eq{$host_lookup_failed}{1}}
          message       = Access temporarily denied. Resolve failed PTR for $sender_host_address
 
   # If DNS works, go ahead and reject them
 
   drop   !hosts        = +debianhosts
          !acl          = acl_spamlovers
-         condition     = ${if and { {!eq{$acl_m_frg}{}}{!match{$sender_host_name}{${rxquote:$acl_m_frg}\N$\N}}}{yes}{no}}
+         condition     = ${if and { {!eq{$acl_m_frg}{}}{!match{$sender_host_name}{${rxquote:$acl_m_frg}\N$\N}}}}
          message       = HELO mismatch Forged HELO for ($sender_helo_name)
 
   # disabled accounts don't even get local mail.
@@ -636,8 +682,8 @@ check_recipient:
          hosts         = !+debianhosts
          message       = mail from <$sender_address> not allowed externally
 
-  deny    condition     = ${if match_domain{$sender_address_domain}{+virtual_domains}{1}{0}}
-          condition     = ${if exists {${extract{directory}{VSENDERDOMAINDATA}{${value}/neversenders}}}{1}{0}}
+  deny    sender_domains= +virtual_domains
+          condition     = ${if exists {${extract{directory}{VSENDERDOMAINDATA}{${value}/neversenders}}}}
           condition     = ${lookup{$sender_address_local_part}lsearch{${extract{directory}{VSENDERDOMAINDATA}{${value}/neversenders}}}{true}}
          message       = no mail should ever come from <$sender_address>
 
@@ -650,26 +696,25 @@ check_recipient:
           message        = X-Packages-FromTo-Same: yes
 
 <%- end -%>
-  deny    condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+  deny    condition      = ${if !eq {$acl_m_prf}{PopconMail}}
           !verify        = sender
 
+  warn    !hosts         = +debianhosts
+          condition      = ${if !eq {$acl_m_prf}{PopconMail}}
+          condition      = ${if >{${eval:$acl_c_scr+0}}{0}}
+          ratelimit      = 10 / 60m / per_rcpt / strict / $sender_host_address
+          log_message    = Sender rate $sender_rate / $sender_rate_period (limit: $sender_rate_limit)
+
   defer   !hosts         = +debianhosts
-          condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+          condition      = ${if !eq {$acl_m_prf}{PopconMail}}
           condition      = ${if >{${eval:$acl_c_scr+0}}{0}}
           ratelimit      = 10 / 60m / per_rcpt / $sender_host_address
           message        = slow down (no reverse dns, mismatched ehlo, dialup, or in blacklists)
 
 <%- if has_variable?("policydweight") && @policydweight -%>
-  # Check with policyd-weight - this only works with a version after etch's,
-  # sadly.  etch's version attempts to hold the socket open, since that's what
-  # postfix expects.  Exim, on the other hand, expects the remote side to close
-  # the socket when it's finished sending data, so it see each transaction as
-  # an incomplete read.  I'm sure there's a way we could force exim to do
-  # something sick and clever to force either the interpretation or the socket
-  # closure, but I'm fairly sure it's now worth it, since the backport of
-  # policyd-weight is trivial.
+  # Check with policyd-weight
   warn  !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
         set acl_m_pw   = ${readsocket{inet:127.0.0.1:12525}\
                           {request=smtpd_access_policy\n\
                            protocol_state=RCPT\n\
@@ -687,39 +732,39 @@ check_recipient:
 
   # Defer on socket error
   defer !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
-        condition      = ${if eq{$acl_m_pw}{socket failure}{yes}{no}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
+        condition      = ${if eq{$acl_m_pw}{socket failure}}
         message        = Cannot connect to policyd-weight. Please try again later.
 
   # Set proposed action to $acl_m_act and message to $acl_m_mes
   warn  !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
         set acl_m_mes  = ${extract{action}{$acl_m_pw}}
         set acl_m_act  = ${sg{$acl_m_pw}{\Naction=[^ ]+ (.*)\n\n\N}{\$1}}
 
   # Add X-policyd-weight header line to message
   warn  !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
         message        = $acl_m_mes
-        condition      = ${if eq{$acl_m_act}{PREPEND}{yes}{no}}
+        condition      = ${if eq{$acl_m_act}{PREPEND}}
 
   # Write log message, if policyd-weight can't run checks
   warn  !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
         log_message    = policyd-weight message: $acl_m_mes
-        condition      = ${if eq{$acl_m_act}{DUNNO}{yes}{no}}
+        condition      = ${if eq{$acl_m_act}{DUNNO}}
 
   # Deny mails which policyd-weight thinks are spam
   deny  !hosts         = +debianhosts
-        condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+        condition      = ${if !eq {$acl_m_prf}{PopconMail}}
         message        = policyd-weight said: $acl_m_mes
-        condition      = ${if eq{$acl_m_act}{550}{yes}{no}}
+        condition      = ${if eq{$acl_m_act}{550}}
 
   # Defer messages when policyd-weight suggests so.
   defer  !hosts         = +debianhosts
-         condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+         condition      = ${if !eq {$acl_m_prf}{PopconMail}}
          message        = policyd-weight said: $acl_m_mes
-         condition      = ${if eq{$acl_m_act}{450}{yes}{no}}
+         condition      = ${if eq{$acl_m_act}{450}}
 
 <%- end -%>
 <%- if @is_rtmaster -%>
@@ -745,7 +790,7 @@ check_recipient:
                                  {/etc/greylistd/whitelist-hosts}{}} : \
                      ${if exists {/var/lib/greylistd/whitelist-hosts}\
                                  {/var/lib/greylistd/whitelist-hosts}{}} 
-    condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+    condition      = ${if !eq {$acl_m_prf}{PopconMail}}
     !authenticated = *
     domains        = +handled_domains
     condition      = ${readsocket{/var/run/greylistd/socket}\
@@ -761,15 +806,15 @@ check_recipient:
   warn
     !senders       = :
     !hosts         = : +debianhosts : WHITELIST
-    condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
-    condition      = ${if def:acl_m_grey {no}{yes}}
+    condition      = ${if !eq {$acl_m_prf}{PopconMail}}
+    condition      = ${if ! def:acl_m_grey}
     set acl_m_grey = $pid.$tod_epoch.$sender_host_port
 
   # and defers the message if postgrey thinks it should be defered ...
   defer
     !senders       = :
     !hosts         = : +debianhosts : WHITELIST
-    condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+    condition      = ${if !eq {$acl_m_prf}{PopconMail}}
     !authenticated = *
     domains        = +handled_domains
     local_parts    = GREYLIST_LOCAL_PARTS
@@ -778,11 +823,7 @@ check_recipient:
                      protocol_name=${uc:$received_protocol}\n\
                      instance=${acl_m_grey}\n\
                      helo_name=${sender_helo_name}\n\
-<%- if scope.call_function('versioncmp', [@lsbmajdistrelease, '8']) <= 0 -%>
-                     client_address=${substr_-3:${mask:$sender_host_address/24}}\n\
-<%- else -%>
                      client_address=${sender_host_address}\n\
-<%- end -%>
                      client_name=${sender_host_name}\n\
                      sender=${sender_address}\n\
                      recipient=$local_part@$domain\n\n
@@ -790,7 +831,7 @@ check_recipient:
                          ${readsocket{/var/run/postgrey/socket}{$acl_m_pgr}\
                                {5s}{}{action=DUNNO}}\
                      }{action=}{}}
-    message        = ${sg{$acl_m_pgr}{^\\w+\\s*}{}}
+    message        = ${sg{$acl_m_pgr}{\N^\w+\s*\N}{}}
     log_message    = greylisted.
     condition      = ${if eq{${uc:${substr{0}{5}{$acl_m_pgr}}}}{DEFER}}
 
@@ -798,12 +839,12 @@ check_recipient:
  warn
     !senders       = :
     !hosts         = : +debianhosts : WHITELIST
-    condition      = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+    condition      = ${if !eq {$acl_m_prf}{PopconMail}}
     !authenticated = *
     domains        = +handled_domains
     local_parts    = GREYLIST_LOCAL_PARTS
     condition      = ${if eq{${uc:${substr_0_7:$acl_m_pgr}}}{PREPEND}}
-    message        = ${sg{$acl_m_pgr}{^\\w+\\s*}{}}
+    message        = ${sg{$acl_m_pgr}{\N^\w+\s*\N}{}}
 
 <%- end -%>
   deny    hosts        = ${if exists{/etc/exim4/host_blacklist}{/etc/exim4/host_blacklist}{}}
@@ -827,6 +868,11 @@ check_recipient:
          domains       = +handled_domains
          !hosts        = +debianhosts : WHITELIST
 
+  deny    message  = host $sender_host_address is listed in $dnslist_domain; see $dnslist_text
+          dnslists = noserver.dnsbl.sorbs.net
+          domains  = +handled_domains
+          !hosts   = +debianhosts : WHITELIST
+
 <%- end -%>
   deny    message  = domain $sender_address_domain is listed in $dnslist_domain; see $dnslist_text
           dnslists = ${if match_domain{$domain}{+virtual_domains}\
@@ -837,6 +883,11 @@ check_recipient:
          domains       = +handled_domains
          !hosts        = +debianhosts : WHITELIST
 
+  deny    message  = domain $sender_address_domain is listed in $dnslist_domain; see $dnslist_text
+          dnslists = nomail.rhsbl.sorbs.net/$sender_address_domain
+          domains  = +handled_domains
+          !hosts   = +debianhosts : WHITELIST
+
 <%- unless @use_smarthost -%>
   deny    domains  = +handled_domains
           local_parts = ${if match_domain{$domain}{+virtual_domains}\
@@ -871,26 +922,34 @@ acl_check_mime:
  accept  verify        = certificate
  accept  hosts         = +debianhosts
 
- discard condition     = ${if <{$message_size}{256000}}
+ discard condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
          condition     = ${if eq {$acl_m_prf}{blackhole}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          log_message   = discarded surbl message for $recipients
 
-  deny   condition     = ${if <{$message_size}{256000}}
-         condition     = ${if eq {$acl_m_prf}{markup}{no}{yes}}
-         condition     = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+  deny   condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
+         condition     = ${if !eq {$acl_m_prf}{markup}}
+         condition     = ${if !eq {$acl_m_prf}{PopconMail}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          log_message   = $acl_m_srb
          message       = $acl_m_srb
 
-  warn   condition     = ${if <{$message_size}{256000}}
+  warn   condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
          condition     = ${if eq {$acl_m_prf}{markup}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          message       = X-Surbl-Hit: $primary_hostname: $acl_m_srb
 
+  # Dump MIME parts to disk. "default" creates sequentially-named files
+  # in <spool_directory>/scan/<message_id>/ which should then be
+  # automagically unlinked after processing.
+  warn   decode        = default
+
+  # Log some information about attachments for debugging
+  warn   log_message   = MIME part [$mime_part_count] -> [${extract{-1}{.}{${lc:$mime_filename}}}] [$mime_content_type]
+
   accept
 
 <%- end -%>
@@ -904,7 +963,7 @@ acl_check_predata:
 #!!# ACL that is used after the DATA command
 check_message:
 
-  # Some people put from hostmaster@something.debian.org in the From
+  # Some people put from postmaster@something.debian.org in the From
   # header.  Take their crack pipe away.
   drop   condition = ${if match{${lc:$h_From:}}{\Npostmaster@([^.]+\.)?debian\.org\N}}
 
@@ -919,7 +978,7 @@ check_message:
 <%- if @is_packagesqamaster -%>
   deny    !hosts  = +debianhosts
           condition = ${if eq {$acl_m_prf}{PTSMail}}
-          condition = ${if def:h_X-PTS-Approved:{false}{true}}
+          condition = ${if !def:h_X-PTS-Approved:}
           message   = messages to the PTS require an X-PTS-Approved header
 
 <%- end -%>
@@ -936,7 +995,7 @@ check_message:
   accept  verify    = certificate
   accept  hosts     = +debianhosts
 
-  deny    condition = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+  deny    condition = ${if !eq {$acl_m_prf}{PopconMail}}
           !verify   = header_syntax
           message   = Invalid header syntax: $acl_verify_message
 
@@ -947,63 +1006,54 @@ check_message:
          condition       = ${if or {{match {$rh_Subject:}{[\200-\377]}}\
                                 {match {$rh_To:}{[\200-\377]}}\
                                 {match {$rh_From:}{[\200-\377]}}\
-                                {match {$rh_Cc:}{[\200-\377]}}}{true}{false}}
-          condition       = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+                                {match {$rh_Cc:}{[\200-\377]}}}}
+          condition       = ${if !eq {$acl_m_prf}{PopconMail}}
          message         = improper use of 8-bit data in message header: message rejected
 
   deny
-         condition       = ${if match {$rh_Subject:}{[^[:print:]]\{8\}}{true}{false}}
-          condition       = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+         condition       = ${if match {$rh_Subject:}{[^[:print:]]\{8\}}}
+          condition       = ${if !eq {$acl_m_prf}{PopconMail}}
          message         = Your mailer is not RFC 2047 compliant: message rejected
 
 <%- if has_variable?("clamd") && @clamd -%>
   discard condition       = ${if eq {$acl_m_prf}{blackhole}}
-  <%- if scope.call_function('versioncmp', [@lsbmajdistrelease, '8']) <= 0 -%>
-          demime          = *
-  <%- end -%>
           malware         = */defer_ok
           log_message     = discarded malware message for $recipients
 
-  deny    condition       = ${if eq {$acl_m_prf}{markup}{no}{yes}}
-          condition       = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
-  <%- if scope.call_function('versioncmp', [@lsbmajdistrelease, '8']) <= 0 -%>
-         demime          = *
-  <%- end -%>
+  deny    condition       = ${if !eq {$acl_m_prf}{markup}}
+          condition       = ${if !eq {$acl_m_prf}{PopconMail}}
           malware         = */defer_ok
           message         = malware detected: $malware_name: message rejected
 
   warn    condition       = ${if eq {$acl_m_prf}{markup}}
-  <%- if scope.call_function('versioncmp', [@lsbmajdistrelease, '8']) <= 0 -%>
-         demime          = *
-  <%- end -%>
           malware         = */defer_ok
           message         = X-malware detected: $malware_name
 
 <%- end -%>
 <%- if @heavy -%>
- discard condition     = ${if <{$message_size}{256000}}
+ discard condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
          condition     = ${if eq {$acl_m_prf}{blackhole}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          log_message   = discarded surbl message for $recipients
 
-  deny   condition     = ${if <{$message_size}{256000}}
-         condition     = ${if eq {$acl_m_prf}{markup}{no}{yes}}
-         condition     = ${if eq {$acl_m_prf}{PopconMail}{no}{yes}}
+  deny   condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
+         condition     = ${if !eq {$acl_m_prf}{markup}}
+         condition     = ${if !eq {$acl_m_prf}{PopconMail}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          log_message   = $acl_m_srb
          message       = $acl_m_srb
 
-  warn   condition     = ${if <{$message_size}{256000}}
+  warn   condition     = ${if <{$message_size}{MAX_SCAN_SIZE}}
          condition     = ${if eq {$acl_m_prf}{markup}}
          set acl_m_srb = ${perl{surblspamcheck}}
-         condition     = ${if eq{$acl_m_srb}{false}{no}{yes}}
+         condition     = ${if !eq{$acl_m_srb}{false}}
          message       = X-Surbl-Hit: $primary_hostname: $acl_m_srb
 
 <%- end -%>
   # Check header_sender except for survey@popcon.d.o
-  deny    condition    = ${if eq{$acl_m_prf}{PopconMail}{false}{true}}
+  deny    condition    = ${if !eq{$acl_m_prf}{PopconMail}}
           !verify      = header_sender
           message      = No valid sender found in the From:, Sender: and Reply-to: headers
 
@@ -1014,7 +1064,7 @@ check_message:
         !authenticated = *
         !verify        = certificate
         !hosts         = +debianhosts
-        condition      = ${if <{$message_size}{256000}}
+        condition      = ${if <{$message_size}{MAX_SCAN_SIZE}}
         spam           = pkg_user : true
         condition      = ${if >{$spam_score_int}{59}}
 
@@ -1056,9 +1106,13 @@ begin routers
 
 <%- if @is_mailrelay -%>
 relay_manualroute:
+  debug_print = "R: relay_manualroute for $local_part@$domain"
   driver = manualroute
   domains = +mailhubdomains
-  transport = remote_smtp
+  transport = ${if forany{${lookup dnsdb{>: mxh=$domain}}}\
+                  {match_domain{$item}{+single_domain_mx}}\
+                  {remote_smtp_single_domain}{remote_smtp}\
+               }
   route_data = ${lookup{$domain}lsearch{/etc/exim4/manualroute}}
   require_files = /etc/exim4/manualroute
 
@@ -1101,8 +1155,15 @@ dnslookup:
   debug_print = "R: dnslookup for $local_part@$domain"
   driver = dnslookup
   domains = !+handled_domains
-  transport = remote_smtp
-  ignore_target_hosts = +reservedaddrs
+  transport = ${if forany{${lookup dnsdb{>: mxh=$domain}}}\
+                  {match_domain{$item}{+single_domain_mx}}\
+                  {remote_smtp_single_domain}{remote_smtp}\
+               }
+  ignore_target_hosts = +reservedaddrs : \
+               ${if forany{${lookup dnsdb{>: mxh=$domain}}}\
+                  {match_domain{$item}{+ipv4_only_domain_mx}}\
+                  {::::/0}{}\
+               }
   no_more
 
 postmasterish:
@@ -1142,9 +1203,9 @@ system_aliases:
 # 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.
 
-# For standard debian setup of one group per user, it is acceptable---normal
+# For standard Debian setup of one group per user, it is acceptable---normal
 # even---for .forward to be group writable. If you have everyone in one
-# group, you should comment out the "modemask" line. Without it, the exim
+# group, you should comment out the "modemask" line. Without it, the Exim
 # default of 022 will apply, which is probably what you want.
 
 userforward_verify:
@@ -1178,7 +1239,7 @@ userforward_verify:
   router_home_directory = ${lookup passwd{$local_part}{${extract{5}{:}{$value}}}fail}
   verify_only
 
-# This is a senmailesque alias file lookup
+# This is a sendmailesque alias file lookup
 virt_aliases:
   debug_print = "R: virt_aliases for $local_part@$domain"
   driver = redirect
@@ -1336,7 +1397,7 @@ rt_force_new_verbose:
   pipe_transport = rt_pipe
   data = "|/usr/bin/rt-mailgate --queue '${lookup{${sg{$local_part}{-comment}{}}}lsearch{RT_QUEUE_MAP}}' --url https://rt.debian.org/ --ca-file /etc/ssl/ca-debian/ca-certificates.crt --action ${if match{$local_part}{.*-comment.*}{comment}{correspond}}"
   headers_remove = Subject
-  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nSubject: ${if and {{first_delivery}{match {$h_subject:}{(?is)(.*?)\\\\[?debian rt\\\\]?[:\\s]*(.*)}}} {$1$2}{$h_subject:}}"
+  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nRT_SUBJECT"
 
 # FIXME: figure out how to generalize this approach so that all of the following would work
 # - rt+NNNN@rt.debian.org          : attach correspondence to ticket (verbose)
@@ -1353,7 +1414,7 @@ rt_force_new_quiesce:
   pipe_transport = rt_pipe
   data = "|/usr/bin/rt-mailgate --queue '${lookup{${sg{$local_part}{-comment}{}}}lsearch{RT_QUEUE_MAP}}' --url https://rt.debian.org/ --ca-file /etc/ssl/ca-debian/ca-certificates.crt --action ${if match{$local_part}{.*-comment.*}{comment}{correspond}}"
   headers_remove = Subject
-  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nX-RT-Mode: quiesce\nSubject: ${if and {{first_delivery}{match {$h_subject:}{(?is)(.*?)\\\\[?debian rt\\\\]?[:\\s]*(.*)}}} {$1$2}{$h_subject:}}"
+  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nX-RT-Mode: quiesce\nRT_SUBJECT"
 
 rt_otherwise:
   debug_print = "R: rt for $local_part@$domain"
@@ -1366,11 +1427,11 @@ rt_otherwise:
   pipe_transport = rt_pipe
   data = "|/usr/bin/rt-mailgate --queue '${lookup{${sg{$local_part}{-(comment|done)}{}}}lsearch{RT_QUEUE_MAP}}' --url https://rt.debian.org/ --ca-file /etc/ssl/ca-debian/ca-certificates.crt --extension ticket --action ${if match{$local_part}{.*-comment.*}{comment}{${if match{$local_part}{.*-done.*}{correspond-resolve}{correspond}}}}"
   headers_remove = Subject
-  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nSubject: ${if and {{first_delivery}{match {$h_subject:}{(?i)(.*?)\\\\[?debian rt\\\\]?[:\\s]*(.*)}}} {$1$2}{$h_subject:}}"
+  headers_add = "Delivered-To: ${local_part}${local_part_suffix}@${domain}\nRT_SUBJECT"
 <%- end -%>
 
-# exim4 fails the router if it can't change to the user/group for delivery
-# during verification.  So we have to seperate the cases of verifying
+# Exim fails the router if it can't change to the user/group for delivery
+# during verification.  So we have to separate the cases of verifying
 # the virts, and delivering to them.  blah.
 
 virt_direct_verify:
@@ -1455,17 +1516,13 @@ virt_users:
   local_part_suffix_optional
   retry_use_local_part
 
-<%=
-out = ""
-if @is_bugsmx
-  domain = 'bugs.debian.org'
-  out = '
+<%- if @is_bugsmx -%>
 # This router delivers for bugs.d.o
 bugs:
   debug_print = "R: bugs for $local_part@$domain"
   driver = accept
   transport = bugs_pipe
-  domains = ' + domain + '
+  domains = bugs.debian.org
   cannot_route_message = Unknown or archived bug
   require_files = /srv/bugs.debian.org/mail/run-procmail
   no_more
@@ -1474,10 +1531,7 @@ bugs:
                   {\N^(\d+)(\d{2})(?:-(?:(?:submit|maintonly|quiet|forwarded|done|close|request|submitter)|(?:unsubscribe|ignore|help|(?:sub(?:scribe|help|yes|approve|reject))|unsubyes|bounce|probe|approve|reject|setlistyes|setlistsilentyes).*))?$\N}\
                {${if exists{/srv/bugs.debian.org/spool/db-h/$2/$1$2.summary}\
               {$local_part}fail}}fail}
-'
-end
-out
-%>
+<%- end -%>
 ######################################################################
 #                      TRANSPORTS CONFIGURATION                      #
 ######################################################################
@@ -1488,11 +1542,12 @@ out
 
 begin transports
 
-# This transport is used for local delivery to user mailboxes. On debian
+# This transport is used for local delivery to user mailboxes. On Debian
 # systems group mail is used so we can write to the /var/mail
 # directory. (The alternative, which most other unixes use, is to deliver
 # as the user's own group, into a sticky-bitted directory)
 local_delivery:
+  debug_print = "T: local_delivery for $local_part@$domain"
   driver = appendfile
   file = /var/mail/${local_part}
   group = mail
@@ -1509,6 +1564,7 @@ local_delivery:
 # want this to happen only when the pipe fails to complete normally.
 
 address_pipe:
+  debug_print = "T: address_pipe for $local_part@$domain"
   driver = pipe
   current_directory = ${home}
   environment = "EXTENSION=${substr_1:${local_part_suffix}}:\
@@ -1523,10 +1579,12 @@ address_pipe:
 # mentioned elsewhere in this configuration file.
 
 address_file:
+  debug_print = "T: address_file for $local_part@$domain"
   driver = appendfile
   return_path_add
 
 address_file_group:
+  debug_print = "T: address_file_group for $local_part@$domain"
   driver = appendfile
   return_path_add
   mode = 0660
@@ -1549,6 +1607,7 @@ address_file_group:
 # are passed to address_directory.
 
 address_directory:
+  debug_print = "T: address_directory for $local_part@$domain"
   driver = appendfile
   check_string = 
   maildir_format
@@ -1560,17 +1619,28 @@ address_directory:
 # option of the forwardfile director. It has a conventional name, since it
 # is not actually mentioned elsewhere in this configuration file.
 address_reply:
+  debug_print = "T: address_reply for $local_part@$domain"
   driver = autoreply
 
 # This transport is used for delivering messages over SMTP connections.
 
 remote_smtp:
+  debug_print = "T: remote_smtp for $local_part@$domain"
   driver = smtp
   connect_timeout = 15s
   delay_after_cutoff = false
   tls_certificate = /etc/exim4/ssl/thishost.crt
   tls_privatekey = /etc/exim4/ssl/thishost.key
 
+remote_smtp_single_domain:
+  debug_print = "T: remote_smtp_single_domain for $local_part@$domain"
+  driver = smtp
+  connect_timeout = 15s
+  delay_after_cutoff = false
+  no_multi_domain
+  tls_certificate = /etc/exim4/ssl/thishost.crt
+  tls_privatekey = /etc/exim4/ssl/thishost.key
+
 <%- if @use_smarthost -%>
 remote_smtp_smarthost:
   debug_print = "T: remote_smtp_smarthost for $local_part@$domain"
@@ -1584,12 +1654,14 @@ remote_smtp_smarthost:
 <%- end -%>
 # Send the message to procmail
 procmail_pipe:
+  debug_print = "T: procmail_pipe for $local_part@$domain"
   driver = pipe
   command = /usr/bin/procmail -a ${substr_1:${local_part_suffix}}
   return_path_add
   user = ${local_part}
 
 bsmtp:
+  debug_print = "T: bsmtp for $local_part@$domain"
   driver = appendfile
   batch_max = 100
   file = ${host}
@@ -1603,6 +1675,7 @@ bsmtp:
 
 <%- if @is_bugsmx -%>
 bugs_pipe:
+  debug_print = "T: bugs_pipe for $local_part@$domain"
   driver = pipe
   command = /srv/bugs.debian.org/mail/run-procmail
   environment = "EXTENSION=${substr_1:${local_part_suffix}}:\
@@ -1628,21 +1701,37 @@ rt_pipe:
 #                      RETRY CONFIGURATION                           #
 ######################################################################
 
-# 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 2 hours and increasing each time by a factor of 1.5, up to 16
-# hours, then retries every 8 hours until 4 days have passed since the first
-# failed delivery.
-
 # Domain               Error       Retries
 # ------               -----       -------
 
-
 begin retry
 
+## Note that retry rules specify when an address / host / mail should
+## become eligible for retrying. They do not specify when the retry
+## attempt will actually occur, as this is dependent on queue run
+## frequency and timing.
+
+# For mail to debian.org addresses, this rule starts with
+# retries every 10 minutes for 2 hours, then increasing retry intervals,
+# starting at 2 hours and increasing each time by a factor of 1.5, up to 16
+# hours, then retries every 8 hours until 14 days have passed since the first
+# failed delivery.
 debian.org            *           F,2h,10m; G,16h,2h,1.5; F,14d,8h
+
+# Bounces should get retried every 10 minutes for up to 2 hours
 *                      * senders=: F,2h,10m
+
+# Temporary errors at RCPT TO get retried at 5 minute intervals for
+# 2 hours, then 10 minute intervals for 4 hours, and finally at 15
+# minute intervals for 4 days. This assumes that the cause of the
+# error will get resolved quickly in most cases.
 *                      rcpt_4xx    F,2h,5m;  F,4h,10m; F,4d,15m
+
+# For all remaining mails, addresses and hosts, this rule starts with
+# retries every 15 minutes for 2 hours, then increasing retry intervals,
+# starting at 2 hours and increasing each time by a factor of 1.5, up to 16
+# hours, then retries every 8 hours until 4 days have passed since the first
+# failed delivery.
 *                      *           F,2h,15m; G,16h,2h,1.5; F,4d,8h
 
 # End of Exim 4 configuration