Ok, let's now start up the "sendmailconfig" script, and go through
the configuration settings: /etc/init.d/sendmail start sendmailconfig.
debian:~# sendmailconfig
Sendmail Configuration
----------------------
By answering the following questions, you can \
configure sendmail for your
system. Default values are determined either by \
your existing configuration
or from common usage.
Press [ENTER]
Mail Name
---------
Your 'mail name' is the hostname portion of \
the address to be shown on
outgoing news and mail messages (following \
the username and @ sign). This
name will be used by other programs besides \
sendmail; it should be the single,
full domain name (FQDN) from which mail \
will appear to originate.
Mail name? [example.com]
|
This is identical to the Exim configuration section in this that we covered previously.
Null Client
-----------
A special configuration known as the "null client" \
can be created for this
host if all mail should be forwarded to a \
central hub via a local SMTP-based
network. This may be a suitable configuration \
if you want to forward all of
your mail to your local Internet service \
provider (ISP) for delivery.
To enable this option, give the name of the \
host to which all mail should be
forwarded. Otherwise leave the option \
empty to disable it.
To remove a prior name, use 'NONE'.
Null client forward host? []
|
A "null client" configuration is suitable for a workstation or
similar system, which simply needs to redirect all its e-mail to the central mail server
on your network. we'll leave this blank for our current configuration.
Smart Host
----------
A "Smart Host" is one that can deliver mail to \
external machines. By using
a "Smart Host", we don't need DNS, or good \
connectivity ourselves. This is
most likely what you want if you have a \
dialup link, or sit behind a firewall.
To enable this option, give the name of the \
host to which all non-local mail
should be forwarded. Otherwise leave \
the option empty.
To remove a prior name, use 'NONE'.
Smart Host:? []
|
A "smart host" configuration is similar to a "null
client", except it also does not require permanent connectivity to the
Internet. This is a good choice if you connect to the Internet using a dial-up
connection. we'll leave this option blank for our current configuration.
Address Canonification
----------------------
Usually sendmail will canonify all addresses by \
consulting a name server and
resolving hosts to their fully qualified domain \
name (FQDN). Under special
circumstances you may want to disable this \
feature, for example if this
machine acts only as a mail gateway.
Disable address canonification? [N]
|
We will leave address canonification enabled. This is analogous to Exim's
"qualify_domain" option.
SMTP Mailer
-----------
If you plan to exchange mail with other computers, \
you should enable the
SMTP mailer. Even if you don't plan to exchange \
mail with other computers,
it is still a good idea to enable this so local \
programs can use it.
Enable the SMTP mailer? [Y]
|
As recommended, we will enable the SMTP mailer.
Masquerade Envelope
-------------------
If you want mail envelopes (as well as mail \
headers) to appear to come from
'example.com', you can enable this option.
Masquerade envelopes? [Y]
|
This is useful if your mail server is called "mail.example.com", but
you wish for your outgoing e-mail to appear as if it is coming from
"example.com". You will normally want to enable this.
All Masquerade
--------------
If enabled, this feature will cause recipient \
addresses to also appear to come
from 'example.com'. Normally they get the \
local hostname.
Although this may be right for ordinary users, \
it can break local aliases. For
example, if you send to "localalias", the \
originating sendmail will find that
alias and send to all members, but send \
the message with
"To: localalias@example.com". Since that \
alias likely does
not exist, replies will fail. Use this feature \
ONLY if you can guarantee that
the ENTIRE namespace of 'example.com' \
supersets all the
local entries. If in doubt, it is safe to leave \
this option disabled.
All masquerade? [N]
|
As recommended, we won't enable "all masquerade".
Don't masquerade mail to local users
-----------------------------------
Send mail to local recipients without masquerading.
Daunt masquerade local? [N]
|
we'll also leave local masquerading disabled.
Always Add Domain
-----------------
If enabled, the local host domain is included \
even on locally delivered mail.
Normally it is not added unless it is \
already present.
Always add domain? [N]
|
This means that local only e-mail will not have the machine name or domain name
appended to it; this is the default behavior, and should be left as is.
Mail Acceptance
---------------
Sendmail is usually configured to accept mail \
for your mail name
(example.com). However, under special \
circumstances you
may not wish sendmail to do this, particularly \
if (and disabling this option
generally requires that) mail for \
'example.com' is MXed
to another host. If in doubt, it is safe to \
leave this option enabled.
Accept mail for 'example.com'? [Y]
|
As directed, it is safe to simply leave this option enabled.
Alternate Names
---------------
In addition to the canonical mail name \
'example.com', you can
add any number of additional alternate \
names to recognize for receiving mail.
If other hosts are MXed to you for local mail, \
this is where you should list
them. This list is saved into the file \
/etc/mail/local-host-names
so it can be changed later as needed.
To answer this question, separate each \
alternate name with a space, or answer
'NONE' to eliminate all alternate names.
Alternate names? []
|
This option is similar to the "local_domains" option in Exim; it
specifies a list of domain names which we consider to be "local" to
this system; ie, we will accept and attempt to deliver e-mail destined for user@domain.
Sendmail keeps a list of these domains in the
"/etc/mail/local-host-names" files.
Trusted Users
-------------
Sendmail allows a special group of users to \
set their envelope "From" address
using the -f option without generating a \
warning message. If you have
software such as Majordomo installed, you \
will want to include the usernames
from such software here. Note that "root", \
"daemon", and "uucp" are included
automatically and do not need to be specified. \
This list is saved into the
file /etc/mail/trusted-users so it can be \
changed later as needed.
To answer this question, separate each \
username with a space, or answer
'NONE' to eliminate all usernames.
Trusted users? []
|
Leave this as the default, unless you have a specific reason to add a trusted user
here. You will normally not need to do this, unless you are running mailing list
software such as Majordomo.
Redirect Feature
----------------
If enabled, this feature will allow you to \
alias old names to
<new-address>.REDIRECT, causing \
sendmail to return mail to the sender with
an error but indicating the recipient's new address.
Enable redirect option? [N]
|
This is a nice option to enable if you have a large userbase with a high rate of
turnover. we'll leave this option disabled for now though.
UUCP Addresses
--------------
Sendmail can be configured to be smart \
about UUCP addresses, or it can do
nothing special with UUCP addresses at all. \
If you care about UUCP, you will
need to do some additional configuration, \
perhaps outside of this script.
*** NOTE *** If you use a smart host or do \
any kind of forwarding (ie
LUSER_RELAY and LOCAL_RELAY), it is \
important that you say "Yes"
here to prevent a multi-level relay hole - \
unless you know for *SURE* that
your smart-host does not deal with UUCP addresses.
(Be safe and just say Y)
Enable UUCP addressing? [Y]
|
UUCP (Unix to Unix Copy Protocol) was the method used for transfering e-mail between
Unix systems before the advent of the Internet. It is still very useful for handling
e-mail for systems which do not have a permanent Internet connection. It's recommended
that you leave this setting on.
Sticky Host
-----------
If enabled, mail sent to 'user@example.com' is \
marked as
"sticky" -- that is, the local addresses aren't \
matched against UDB and don't
go through ruleset 5. This is used if you want \
a setup where 'user' is not
necessarily the same as 'user@example.com', \
e.g., to make
a distinct domain-wide namespace. \
If in doubt, it is safe to leave this
option disabled.
Enable sticky host option? [N]
|
As recommended, you can leave this option disabled.
DNS
---
If you are directly connected to the Internet and \
have access to a domain
name server, you should enable this option.
Enable DNS? [Y]
|
If you are configuring a dial-up system, you can disable this option; otherwise, you
should always have it enabled.
Best MX is Local
----------------
If enabled, this option will cause sendmail to accept \
mail as though locally
addressed for any host that lists this machine as the \
best possible MX record.
This generates additional DNS traffic, but should be \
OK for low-to-medium
traffic hosts. N.B.: This feature is fundamentally \
incompatible with wildcard
MX records. If you have a wildcard MX record that \
matches your domain, you
cannot use this feature.
Assume best MX is local? [N]
|
We will leave this disabled for now.
Mailertable
-----------
If enabled, this option causes sendmail to read \
mail routing rules from
the text file /etc/mail/mailertable. This is needed \
for unusual mailers like
ifmail and fax programs.
More information is in \
/usr/share/doc/sendmail-doc/op/op.txt.gz.
Enable the mailertable feature? [N]
|
You should peruse the documentation found in
"/usr/share/doc/sendmail-doc/op/op.txt.gz" to get an idea of what you
can do here; but we can leave this disabled for now.
Sendmail Restricted Shell
-------------------------
If enabled, this option causes sendmail to use the \
sendmail restricted shell
program (smrsh) instead of /bin/sh for mailing to \
programs. This improves your
ability to control what gets run via email; only \
those programs which appear
in a special directory can be run. If you enable \
this option, please carefully
read the smrsh(8) man page for further information.
Use the Sendmail Restricted Shell (smrsh)? [Y]
|
This is a desired security option for Sendmail, and should be enabled unless you have
a very specific reason not to do so.
Mailer Name
-----------
You can change the name used for internally \
generated outgoing messages.
Usually this is 'MAILER-DAEMON' but it would \
not be unreasonable to change
it to something such as 'postmaster'.
Mailer name? [MAILER-DAEMON]
|
Leave this as "MAILER-DAEMON".
Me Too
------
Sendmail normally excludes the sender address \
from group expansion. Enabling
this option will cause the sender to be included.
Enable me too option? [N]
|
This option is self-explanatory; you can simply leave it at the default.
Message Timeouts
----------------
Sendmail will issue a warning message to the \
sender if it can't deliver a
message within a reasonable amount of time. \
It will also send a failure
notification and give up trying to deliver the \
message if it can't deliver it
after an unreasonable amount of time.
You can configure the message timeouts after \
which warning and failure
notifications are sent. Sendmail's defaults are 4 \
hours and 5 days (4h/5d),
respectively, but many people feel warnings after \
only 4 hours are premature.
Message timeouts? [4h/5d]
|
You can leave the values at the default, unless you are wanting to tweak your mail system.
Configuration Complete
----------------------
Advanced configuration, such as alternate mailers, \
the use of mailertables,
Bitnet domains, and UUCP domains can be \
accomplished by manually editing the
/etc/mail/sendmail.mc configuration file and rerunning
'/usr/sbin/sendmailconfig' to generate the \
appropriate /etc/mail/sendmail.cf
file. (Local changes made at the end of /etc/mail/sendmail.mc
will be preserved by '/usr/sbin/sendmailconfig'.)
|
