-## $Cambridge: exim/doc/doc-src/FAQ.src,v 1.5 2004/11/12 15:03:40 ph10 Exp $
##
## This file is processed by Perl scripts to produce an ASCII and an HTML
## version. Lines starting with ## are omitted. The markup used with paragraphs
You can test the link using pings of large packets and see what works:
-==> ping -s host 2048
+==> ping -s host 2048
Try reducing the MTU on the sending host:
-==> ifconfig le0 mtu 1300
+==> ifconfig le0 mtu 1300
Alternatively, you can reduce the size of the buffer Exim uses for SMTP
output by putting something like
a temporary error. Here are some possibilities:
(1) The messages to \(aol.com)\ got put in your queue, but no previous
- delivery attempt occured before you did the \-R-\. This might have been
+ delivery attempt occurred before you did the \-R-\. This might have been
because of your settings of \queue_only_load\, \smtp_accept_queue\, or any
other option that caused no immediate delivery attempt on arrival. If
this is the case, you can try using \-qqR-\ instead of \-R-\.
==> deny hosts = *.x.example
If at all possible, you should use IP addresses instead of host
- names in blocking lists in order to to avoid this problem.
+ names in blocking lists in order to avoid this problem.
You can use the \-bh-\ option to get more information about what is
happening at the start of a connection. However, note that the \-bh-\
second solution is used, users can empty their mailboxes by updating
them, but cannot delete them.
- If your problem involves mail to \/root/\, see also Q0507.
+ If your problem involves mail to \/root/\, see also Q0039.
Q0037: I am experiencing mailbox locking problems with Sun's \"mailtool"\ used
If you are running Exim with an alternate configuration file using a
command such as \"exim -C altconfig..."\, remember that the use of -C
- takes away Exim's root privilege.
+ takes away Exim's root privilege, unless \\TRUSTED_CONFIG_LIST\\
+ is set in \(Local/Makefile)\ and the corresponding file contains a
+ prefix which matches the alternative configuration file being used.
Check that you have defined the spool directory correctly by running
==> /usr/lib/sendmail -bz
- in some start-up script (e.g. \(/etc/init.d/mail)\) immedately before
+ in some start-up script (e.g. \(/etc/init.d/mail)\) immediately before
==> /usr/lib/sendmail -bd -q15m
trying to run an \%autoreply%\ transport. Why is this?
A0065: When Exim is called with -C, it passes on -C to any instances of itself
- that it calls (so that the whole sequence uses the same config file). If
- it's running as \/exim/\ when it does this, all is well. However, if it
- happens as a consequence of a non-privileged user running \%autoreply%\,
- the called Exim gives up its root privilege. Then it can't write to the
- spool.
-
- This means that you can't use -C (even as \/root/\) to run an instance of
- Exim that is going to try to run \%autoreply%\ from a process that is
- neither \/root/\ nor \/exim/\. Because of the architecture of Exim (using
- re-execs to regain privilege), there isn't any way round this
- restriction. Therefore, the only way you can make this scenario work is
- to run the \%autoreply%\ transport as \/exim/\ (that is, the user that
- owns the Exim spool files). This may be satisfactory for autoreplies
- that are essentially system-generated, but of course is no good for
- autoreplies from unprivileged users, where you want the \%autoreply%\
- transport to be run as the user. To get that to work with an alternate
- configuration, you'll have to use two Exim binaries, with different
- configuration file names in each. See S001 for a script that patches
- the configuration name in an Exim binary.
+ that it calls (so that the whole sequence uses the same config file).
+ However, Exim gives up its root privilege if any user except \/root\/
+ passes a -C option to use a non-default configuration file, and that
+ includes the case where Exim re-execs itself to regain root privilege.
+ Thus it can't write to the spool.
+
+ The fix for this is to use the \\TRUSTED_CONFIG_LIST\\ build-time
+ option. This defines a file containing a list of 'trusted' prefixes for
+ configuration files. Any configuration file specified with -C, if it
+ matches a prefix listed in that file, will be used without dropping root
+ privileges (as long as it is not writeable by a non-root user).
Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?
by a \"mail.info"\ descriptor).
Test this by running the command:
-==> logger -p mail.notice test
+==> logger -p mail.notice test
and seeing which logs it goes into. From Exim release 4.31 it is
possible to disable the rejectlog by setting \write_rejectlog\ false.
taken from Exim's change log:
When Exim is receiving multiple messages on a single connection, and
- spinning off delivery processess, it sets the SIGCHLD signal handling to
+ spinning off delivery processes, it sets the SIGCHLD signal handling to
SIG_IGN, because it doesn't want to wait for these processes. However,
because on some OS this didn't work, it also has a paranoid call to
\^waitpid()^\ in the loop to reap any children that have finished. Some
ensure that this happens throughout the build, it's best to export it in
your environment:
-==> MAKEFLAGS='-B'
- export MAKEFLAGS
- make
+==> MAKEFLAGS='-B'
+ export MAKEFLAGS
+ make
Q0116: I have tried to build Exim with Berkeley DB 3 and 4, but I always get
==> adduser exim
- (3) Now you can prepare to build Exim. Go to \?http://www.exim.org?\ or
- one of its mirrors, or the master ftp site
+ (3) Now you can prepare to build Exim. Go to \?https://www.exim.org?\ or
+ one of its mirrors, or the master FTP site
\?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4?\, and download
\(exim-4.20.tar.gz)\ or whatever the current release is. Then:
with MX records pointing to \"localhost"\ (or other names with A records
that specify 127.0.0.1), which causes this behaviour. You can use the
\ignore_target_hosts\ option to get Exim to ignore these records. The
- default contiguration does this. For more discussion, see Q0319. For
+ default configuration does this. For more discussion, see Q0319. For
other cases:
(1) If the domain is meant to be handled as a local domain, there
Q0311: When a DNS lookup for MX records fails to complete, why doesn't Exim
- send the messsage to the host defined by the A record?
+ send the message to the host defined by the A record?
A0311: The RFCs are quite clear on this. Only if it is known that there are no
MX records is an MTA allowed to make use of the A record. When an MX
==> # Don't allow domains whose single MX (or A) record is a
# "special-use IPv4 address", as listed in RFC 3330.
ignore_target_hosts = \
- # Hosts on "this network"; RFC 1700 (page 4) states that these
- # are only allowed as source addresses
- 0.0.0.0/8 : \
- # Private networks, RFC 1918
- 10.0.0.0/8 : 172.16.0.0/12 : 192.168.0.0/16 : \
- # Internet host loopback address, RFC 1700 (page 5)
- 127.0.0.0/8 : \
- # "Link local" block
- 169.254.0.0/16 : \
- # "TEST-NET" - should not appear on the public Internet
- 192.0.2.0/24 : \
- # 6to4 relay anycast addresses, RFC 3068
- 192.88.99.0/24 : \
- # Network interconnect device benchmark testing, RFC 2544
- 198.18.0.0/15 : \
- # Multicast addresses, RFC 3171
- 224.0.0.0/4 : \
- # Reserved for future use, RFC 1700 (page 4)
- 240.0.0.0/4
+ # Hosts on "this network"; RFC 1700 (page 4) states that these
+ # are only allowed as source addresses
+ 0.0.0.0/8 : \
+ # Private networks, RFC 1918
+ 10.0.0.0/8 : 172.16.0.0/12 : 192.168.0.0/16 : \
+ # Internet host loopback address, RFC 1700 (page 5)
+ 127.0.0.0/8 : \
+ # "Link local" block
+ 169.254.0.0/16 : \
+ # "TEST-NET" - should not appear on the public Internet
+ 192.0.2.0/24 : \
+ # 6to4 relay anycast addresses, RFC 3068
+ 192.88.99.0/24 : \
+ # Network interconnect device benchmark testing, RFC 2544
+ 198.18.0.0/15 : \
+ # Multicast addresses, RFC 3171
+ 224.0.0.0/4 : \
+ # Reserved for future use, RFC 1700 (page 4)
+ 240.0.0.0/4
Q0320: How can I arrange for all mail to \*user@some.domain*\ to be forwarded
Q0409: I want mail for any local part at certain virtual domains to go
to a single address for each domain.
-A0409: One way to to this is
+A0409: One way to do this is
==> virtual:
driver = redirect
any more. How can I arrange to delete any mail that is sent to them?
A0419: To reject them at SMTP time, with a customized error message, place
- statments like this in the ACL:
+ statements like this in the ACL:
==> deny message = The domain $domain is obsolete
domains = lsearch;/etc/exim/obsolete.domains
to scan email messages at SMTP time. \^elspy^\ also includes a small
Python library with common mail-scanning tools, including an interface
to SpamAssassin and a simple but effective virus detector. You can
- optain \^elspy^\ from \?http://elspy.sourceforge.net/?\.
+ obtain \^elspy^\ from \?http://elspy.sourceforge.net/?\.
Q0511: Whenever my system filter uses a \mail\ command to send a message, I get
==> majordomo: |/local/mail/majordomo ...
then Exim has to be told what uid/gid to use for the delivery. This can
- be done either on the routerr that handles the address, or on the
+ be done either on the router that handles the address, or on the
transport that actually does the delivery. If a pipe is going to run a
setuid program, then it doesn't matter what uid Exim starts it out with,
and so the most straightforward thing is to put
Q0604: I want to use MMDF-style mailboxes. How can I get Exim to append the
- ctrl-A characters that separate indvidual emails?
+ ctrl-A characters that separate individual emails?
A0604: Set the \message_suffix\ option in the \%appendfile%\ transport. In fact,
for MMDF mailboxes you need a prefix as well as a suffix to get it
\use_crlf\ option on the \%pipe%\ transport (tmail prefers \"@\r@\n"\
terminations) message bodies started to vanish.
-A0606: You need to unset the \mesage_prefix\ option, or change it so that its
+A0606: You need to unset the \message_prefix\ option, or change it so that its
default \"@\n"\ terminator becomes \"@\r@\n"\. For example, the
transport could be:
==> local_delivery_mbx:
- driver = pipe
- command = /usr/local/bin/tmail $local_part
- user = exim
- current_directory = /
+ driver = pipe
+ command = /usr/local/bin/tmail $local_part
+ user = exim
+ current_directory = /
use_crlf
message_prefix =
==> deny message = ${lookup{$sender_address=>$local_part@$domain}\
lsearch{/that/file}}
condition = ${lookup{$sender_address=>$local_part@$domain}\
- lsearch{/that/file}}{yes}{no}}
+ lsearch{/that/file}{yes}{no}}
The condition is tested first. If the lookup succeeds, the condition
succeeds so access is denied. The message is then expanded, but the
do not block legitimate mail. With that proviso, you can do it using
something like this in an ACL:
-==> drop message = HELO doesn't look like a hostname
- log_message = Not a hostname
- condition = ${if match{$sender_helo_name} \
- {\N^[^.].*\.[^.]+$\N}{no}{yes}}
+==> drop message = HELO doesn't look like a hostname
+ log_message = Not a hostname
+ condition = ${if match{$sender_helo_name} \
+ {\N^[^.].*\.[^.]+$\N}{no}{yes}}
This means: Drop the HELO unless it contains a dot somewhere in the HELO
string, but the string may not begin or end with a dot. Thus, the
names, but if mail comes in for an upper case login name, it doesn't
get rewritten.
-==> *@my.domain ${lookup{$1}dbm{/usr/lib/exim/longforms}\
- {$value}fail}@my.domain bcfrtFT
+==> *@my.domain ${lookup{$1}dbm{/usr/lib/exim/longforms}\
+ {$value}fail}@my.domain bcfrtFT
The longforms database has entries of the form:
are rewriting. If you are rewriting recipient addresses for your local
domain, you can do:
-==> *@dom.ain ${lookup{$1}dbm{/wher/ever}{$value}{failaddr}} Ehq
+==> *@dom.ain ${lookup{$1}dbm{/wher/ever}{$value}{failaddr}} Ehq
and in your alias file put something like
-==> failaddr: :fail: Rewriting failed
+==> failaddr: :fail: Rewriting failed
This fails a single recipient - others are processed independently.
but it is important to some people - especially if by some unfortunate
accident the lowercased word is something indecent.
- You can trivally force lower casing by means of the \"${lc:"\ operator.
+ You can trivially force lower casing by means of the \"${lc:"\ operator.
Instead of \"$domain"\ write \"${lc:$domain}"\.
==> headers add "New-Subject: SPAM: $h_subject:"
headers remove subject
- neaders add "Subject: $h_new-subject:"
+ headers add "Subject: $h_new-subject:"
headers remove new-subject
This trick works only in system filters, where the commands are obeyed
up earlier on some types of file system, compared with others.
Exim was not designed for handling large queues. If you are in an
- enviroment where lots of messages remain on the queue for long periods
+ environment where lots of messages remain on the queue for long periods
of time, consider implementing a back up host to which you pass these
messages, so that the main host's queue remains short. You can use
\fallback_hosts\ to do this, or a router that is conditional on
to enable my clients to use TLS. However, clients other than Exim
refuse to accept this certificate. What's wrong?
-A1701: It seems that some clients require that the certificate presented by
- the server be a user (also called ``leaf'' or ``site'') certificate, and not
- a self-signed certificate. In this situation, the self-signed
- certificate must be installed on the client as a trusted root
- \*certification authority*\ (CA), and the certificate used by the server
- must be a user certificate signed with that self-signed certificate.
-
- For information on creating self-signed CA certificates and using them
- to sign user certificates, see the \*General implementation overview*\
- chapter of the Open-source PKI book, available online at
- \?http://ospkibook.sourceforge.net/?\. Here is a quick overview. First,
- read this message:
-
- \?http://www.FreeBSD.org/cgi/mid.cgi?id=3C3F3A93.C1ECF9B0%40mindspring.com?\
-
- Then, follow the instructions found on these two (consecutive) pages:
-
- \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/initialisation.htm?\
- \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/keygensign.htm?\
-
- Two points on the PKI Book literature:
-
- (1) It's assumed that it's okay to use a passphrase-protected key to
- encrypt the user/site/leaf certificate. If this isn't acceptable,
- you seem to be able to strip out the passphrase as follows:
-
-==> openssl rsa -in user.key -our user.key.new
- mv user.key.new
-
- This should be done immediately after \(user.key)\ is created.
-
- (2) The \*sign.sh*\ script is available in the \*mod_ssl*\ distribution,
- available at \?http://www.modssl.org/source/?\.
-
- Having followed the instructions, you end up with the following files:
-
- (a) \(ca.crt)\
-
- This file should be installed into the client software as a trusted
- root certification authority. In Windows XP, this can be done as follows:
-
- \#\#Call the file \(ca_cert.cer)\
- [[br]]
- \#\#Double-click on the file
- [[br]]
- \#\#"Install Certificate";
- [[br]]
- \#\#"Next"
- [[br]]
- \#\#"Place all certificates in the following store"
- [[br]]
- \#\#"Browse..."
- [[br]]
- \#\#"Trusted Root Certification Authorities"
- [[br]]
- \#\#"OK"
- [[br]]
- \#\#"Next"
- [[br]]
- \#\#"Finish"
- [[br]]
- \#\#"Yes"
- [[br]]
- \#\#"OK"
-
- (b) \(user.crt)\ and \(user.key)\
-
- These files should be installed into the server software. In Exim, this
- can be done by adding these lines to the configuration file:
-
-==> tls_certificate = /usr/local/etc/exim/tls_cert
- tls_privatekey = /usr/local/etc/exim/tls_key
+A1701: Don't use a self-signed certificate today. Use a certificate from a
+ certificate authority, whether your own private certificate authority or
+ a free CA such as Let's Encrypt.
- Then install \(user.crt)\ and \(user.key)\ under the names \(tls_cert)\
- and \(tls_key)\ in the appropriate directory.
+ The exim.org setup uses Let's Encrypt, using the lego tooling and a small
+ shell wrapper to let the certificates be automatically renewed via cron.
+ \?https://github.com/xenolf/lego?\
Q1702: How can I arrange for Exim to advertise support for SMTP authentication
only when the session is encrypted?
land for Majordomo at the same time.
A9604: The problem appears to be the number of open files the system can
- handle. This is changable by using the proc filesystem. To your
+ handle. This is changeable by using the proc filesystem. To your
\(/etc/rc.d/rc.local)\ file append something like the following:
==> # Now System is up, Modify kernel parameters for max open etc.
==> if [ -f /proc/sys/kernel/file-max ]; then
- echo 16384 >> /proc/sys/kernel/file-max
+ echo 16384 >> /proc/sys/kernel/file-max
fi
if [ -f /proc/sys/kernel/inode-max ]; then
- echo 24576 >> /proc/sys/kernel/inode-max
+ echo 24576 >> /proc/sys/kernel/inode-max
fi
if [ -f /proc/sys/kernel/file-nr ]; then
- echo 2160 >> /proc/sys/kernel/file-nr
+ echo 2160 >> /proc/sys/kernel/file-nr
fi
By echoing the value you want for file-max to the file \(file-max)\ etc.,
names of the form Fnnn are filter file fragments; those with names of the form
Lnnn are sample \^^local_scan()^^\ functions, and those with names of thf form
Snnn are scripts of various kinds. There are other examples of
-\^^local_scan()^^\ functions at a number of web sites (for example,
+\^^local_scan()^^\ functions at a number of websites (for example,
\?http://marc.merlins.org/linux/exim/sa.html?\).
There are gaps in the C and F numbers because I have omitted the Exim 3 samples
C042: ``Since the Exim 4 configuration needed to get Mailman to work differs a
little bit from Exim 3 and since I still haven't seen a recipe for
Mailman with Exim 4, I'm providing my configuration (based heavily on
- \?http://www.exim.org/howto/mailman.html?\).''
+ \?https://www.exim.org/howto/mailman21.html?\).''
C043: ``Attached is an Exim 4 config file which is designed for an Exim server
that is put in front of an Exchange 5.5 system but which verifies the
git://git.exim.org / exim.git / blobdiff