SENDMAIL Configuration for Comcast Cable and LunarPages - Revision history

Dlk at 14:34, 31 December 2019

2019-12-31T14:34:55Z

Dlk at 05:37, 2 September 2012

2012-09-02T05:37:52Z

Dlk at 19:19, 10 January 2008

2008-01-10T19:19:17Z

Dlk at 13:47, 9 January 2008

2008-01-09T13:47:40Z

Dlk at 13:25, 9 January 2008

2008-01-09T13:25:52Z

Dlk at 17:15, 6 September 2006

2006-09-06T17:15:37Z

Dlk at 17:07, 6 September 2006

2006-09-06T17:07:21Z

Dlk at 17:05, 6 September 2006

2006-09-06T17:05:11Z

New page

I have some Linux hosts in my network at home that want to send system messages using SENDMAIL and SMTP. Neither LunarPages nor Comcast have open relays that supports this. Configuring sendmail masquerading will allow these systems to send mail via the LunarPages' or Comcast's SMTP server.

Both LunarPages and Comcast require that the MAIL FROM: address specified during the SMTP dialog match the From: header that’s part of the message data. They also require that the sending e-mail address exist. I changed the default mail routing in my ISP's settings for daveking.com to “:blackhole:” instead of “:fail:” so that any and all e-mail address would be accepted for that domain.

I turned on masquerading in /etc/mail/sendmail.mc. By default, masquerading is disabled for the root user. To enable masquerading for root I commented out the EXPOSED_USER statement in sendmail.mc. The lines I changed are marked with “>>” below.

<pre>
divert(-1)dnl
dnl #
dnl # This is the sendmail macro config file for m4. If you make changes to
dnl # /etc/mail/sendmail.mc, you will need to regenerate the
dnl # /etc/mail/sendmail.cf file by confirming that the sendmail-cf package is
dnl # installed and then performing a
dnl #
dnl # make -C /etc/mail
dnl #
include(`/usr/share/sendmail-cf/m4/cf.m4')dnl
VERSIONID(`setup for Red Hat Linux')dnl
OSTYPE(`linux')dnl
dnl #
dnl # default logging level is 9, you might want to set it higher to
dnl # debug the configuration
dnl #
dnl define(`confLOG_LEVEL', `9')dnl
dnl #
dnl # Uncomment and edit the following line if your outgoing mail needs to
dnl # be sent out through an external mail server:
dnl #
>> define(`SMART_HOST',`ganymede.lunarpages.com')dnl
>> dnl # define(`SMART_HOST',`smtp.comcast.net')dnl
dnl #
define(`confDEF_USER_ID',``8:12'')dnl
dnl define(`confAUTO_REBUILD')dnl
define(`confTO_CONNECT', `1m')dnl
define(`confTRY_NULL_MX_LIST',true)dnl
define(`confDONT_PROBE_INTERFACES',true)dnl
define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl
define(`ALIAS_FILE', `/etc/aliases')dnl
define(`STATUS_FILE', `/var/log/mail/statistics')dnl
define(`UUCP_MAILER_MAX', `2000000')dnl
define(`confUSERDB_SPEC', `/etc/mail/userdb.db')dnl
define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl
define(`confAUTH_OPTIONS', `A')dnl
dnl #
dnl # The following allows relaying if the user authenticates, and disallows
dnl # plaintext authentication (PLAIN/LOGIN) on non-TLS links
dnl #
dnl define(`confAUTH_OPTIONS', `A p')dnl
dnl #
dnl # PLAIN is the preferred plaintext authentication method and used by
dnl # Mozilla Mail and Evolution, though Outlook Express and other MUAs do
dnl # use LOGIN. Other mechanisms should be used if the connection is not
dnl # guaranteed secure.
dnl # Please remember that saslauthd needs to be running for AUTH.
dnl #
dnl TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
dnl define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
dnl #
dnl # Rudimentary information on creating certificates for sendmail TLS:
dnl # cd /usr/share/ssl/certs; make sendmail.pem
dnl # Complete usage:
dnl # make -C /usr/share/ssl/certs usage
dnl #
dnl define(`confCACERT_PATH',`/etc/pki/tls/certs')dnl
dnl define(`confCACERT',`/etc/pki/tls/certs/ca-bundle.crt')dnl
dnl define(`confSERVER_CERT',`/etc/pki/tls/certs/sendmail.pem')dnl
dnl define(`confSERVER_KEY',`/etc/pki/tls/certs/sendmail.pem')dnl
dnl #
dnl # This allows sendmail to use a keyfile that is shared with OpenLDAP's
dnl # slapd, which requires the file to be readble by group ldap
dnl #
dnl define(`confDONT_BLAME_SENDMAIL',`groupreadablekeyfile')dnl
dnl #
dnl define(`confTO_QUEUEWARN', `4h')dnl
dnl define(`confTO_QUEUERETURN', `5d')dnl
dnl define(`confQUEUE_LA', `12')dnl
dnl define(`confREFUSE_LA', `18')dnl
define(`confTO_IDENT', `0')dnl
dnl FEATURE(delay_checks)dnl
FEATURE(`no_default_msa',`dnl')dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(redirect)dnl
FEATURE(always_add_domain)dnl
FEATURE(use_cw_file)dnl
FEATURE(use_ct_file)dnl
dnl #
dnl # The following limits the number of processes sendmail can fork to accept
dnl # incoming messages or process its message queues to 12.) sendmail refuses
dnl # to accept connections once it has reached its quota of child processes.
dnl #
dnl define(`confMAX_DAEMON_CHILDREN', 12)dnl
dnl #
dnl # Limits the number of new connections per second. This caps the overhead
dnl # incurred due to forking new sendmail processes. May be useful against
dnl # DoS attacks or barrages of spam. (As mentioned below, a per-IP address
dnl # limit would be useful but is not available as an option at this writing.)
dnl #
dnl define(`confCONNECTION_RATE_THROTTLE', 3)dnl
dnl #
dnl # The -t option will retry delivery if e.g. the user runs over his quota.
dnl #
FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
FEATURE(`blacklist_recipients')dnl
>> dnl # EXPOSED_USER(`root')dnl
dnl #
dnl # For using Cyrus-IMAPd as POP3/IMAP server through LMTP delivery uncomment
dnl # the following 2 definitions and activate below in the MAILER section the
dnl # cyrusv2 mailer.
dnl #
dnl define(`confLOCAL_MAILER', `cyrusv2')dnl
dnl define(`CYRUSV2_MAILER_ARGS', `FILE /var/lib/imap/socket/lmtp')dnl
dnl #
dnl # The following causes sendmail to only listen on the IPv4 loopback address
dnl # 127.0.0.1 and not on any other network devices. Remove the loopback
dnl # address restriction to accept email from the internet or intranet.
dnl #
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
dnl #
dnl # The following causes sendmail to additionally listen to port 587 for
dnl # mail from MUAs that authenticate. Roaming users who can't reach their
dnl # preferred sendmail daemon due to port 25 being blocked or redirected find
dnl # this useful.
dnl #
dnl DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl
dnl #
dnl # The following causes sendmail to additionally listen to port 465, but
dnl # starting immediately in TLS mode upon connecting. Port 25 or 587 followed
dnl # by STARTTLS is preferred, but roaming clients using Outlook Express can't
dnl # do STARTTLS on ports other than 25. Mozilla Mail can ONLY use STARTTLS
dnl # and doesn't support the deprecated smtps; Evolution <1.1.1 uses smtps
dnl # when SSL is enabled-- STARTTLS support is available in version 1.1.1.
dnl #
dnl # For this to work your OpenSSL certificates must be configured.
dnl #
dnl DAEMON_OPTIONS(`Port=smtps, Name=TLSMTA, M=s')dnl
dnl #
dnl # The following causes sendmail to additionally listen on the IPv6 loopback
dnl # device. Remove the loopback address restriction listen to the network.
dnl #
dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')dnl
dnl #
dnl # enable both ipv6 and ipv4 in sendmail:
dnl #
dnl DAEMON_OPTIONS(`Name=MTA-v4, Family=inet, Name=MTA-v6, Family=inet6')
dnl #
dnl # We strongly recommend not accepting unresolvable domains if you want to
dnl # protect yourself from spam. However, the laptop and users on computers
dnl # that do not have 24x7 DNS do need this.
dnl #
FEATURE(`accept_unresolvable_domains')dnl
dnl #
dnl FEATURE(`relay_based_on_MX')dnl
dnl #
dnl # Also accept email sent to "localhost.localdomain" as local email.
dnl #
LOCAL_DOMAIN(`localhost.localdomain')dnl
dnl #
dnl # The following example makes mail from this host and any additional
dnl # specified domains appear to be sent from mydomain.com
dnl #
>> MASQUERADE_AS(`daveking.com')dnl
dnl #
dnl # masquerade not just the headers, but the envelope as well
dnl #
>> FEATURE(masquerade_envelope)dnl
dnl #
dnl # masquerade not just @mydomainalias.com, but @*.mydomainalias.com as well
dnl #
>> FEATURE(masquerade_entire_domain)dnl
dnl #
>> FEATURE(allmasquerade)dnl
dnl #
dnl MASQUERADE_DOMAIN(localhost)dnl
dnl MASQUERADE_DOMAIN(localhost.localdomain)dnl
dnl MASQUERADE_DOMAIN(mydomainalias.com)dnl
dnl MASQUERADE_DOMAIN(mydomain.lan)dnl
MAILER(smtp)dnl
MAILER(procmail)dnl
dnl MAILER(cyrusv2)dnl
</pre>

Then, to activate these changes:
make -C /etc/mail
service sendmail restart

Mail for the root user can be redirected by specifying an alias for the root userid in the file /etc/aliases. Uncomment and set the alias for root at the bottom of /etc/aliases and then run the command “newaliases”.

Note: The command “sendmail -d0.1 -bv” shows the version of sendmail in use.

← Older revision		Revision as of 14:34, 31 December 2019
Line 214:		Line 214:

	[[Category:Linux]]		[[Category:Linux]]
		+	[[Category:EMail]]

@@ Line 1: / Line 1: @@
 I have some Linux hosts in my network at home that want to send system messages using SENDMAIL and SMTP. Neither LunarPages nor Comcast have open relays that supports this. Configuring sendmail masquerading will allow these systems to send mail via the LunarPages' or Comcast's SMTP server.
-Both LunarPages and Comcast require that the MAIL FROM: address specified during the SMTP dialog match the From: header that&rsquo;s part of the message data. They also require that the sending e-mail address exist. I changed the default mail routing in my ISP's settings for daveking.com to &ldquo;:blackhole:&rdquo; instead of &ldquo;:fail:&rdquo; so that any and all e-mail address would be accepted for that domain.  Both of them have blocked SMTP port 25 and require that you use SUBMISSION port 587.  So far, since this port change, I have only configured SENDMAIL for use with LunarPages.  They do not seem to require authentication so all that's necessary is to set the relay options to use port 587 instead of the default, 25.  There are instructions for Comcast, who do apparently require authentication, at http://www.linuxha.com/other/sendmail/index.html but I haven't tried them yet.
+Both LunarPages and Comcast require that the MAIL FROM: address specified during the SMTP dialog match the From: header that&rsquo;s part of the message data. They also require that the sending e-mail address exist. I changed the default mail routing in my ISP's settings for daveking.com to &ldquo;:blackhole:&rdquo; instead of &ldquo;:fail:&rdquo; so that any and all e-mail address would be accepted for that domain.
-I turned on masquerading in /etc/mail/sendmail.mc. By default, masquerading is disabled for the root user. To enable masquerading for root I commented out the EXPOSED_USER statement in sendmail.mc. The lines I changed are marked with &ldquo;>>&rdquo; below.
+I turned on masquerading in /etc/mail/sendmail.mc. By default, masquerading is disabled for the root user. To enable masquerading for root I commented out the EXPOSED_USER statement in sendmail.mc.
 <pre>
@@ Line 27: / Line 33: @@
      dnl # be sent out through an external mail server:
      dnl #
 >>  define(`SMART_HOST',`ganymede.lunarpages.com')dnl
 >>  define(`RELAY_MAILER_ARGS', `TCP $h 587')
@@ Line 81: / Line 88: @@
      FEATURE(`no_default_msa',`dnl')dnl
      FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
      FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
      FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
@@ Line 192: / Line 202: @@
 Note: The command &ldquo;sendmail -d0.1 -bv&rdquo; shows the version of sendmail in use.
 [[Category:Linux]]

← Older revision		Revision as of 17:15, 6 September 2006
Line 192:		Line 192:

	Note: The command “sendmail -d0.1 -bv” shows the version of sendmail in use.		Note: The command “sendmail -d0.1 -bv” shows the version of sendmail in use.
		+
		+	[[Category:Linux]]

@@ Line 189: / Line 189: @@
      dnl MASQUERADE_DOMAIN(mydomainalias.com)dnl
      dnl MASQUERADE_DOMAIN(mydomain.lan)dnl
      MAILER(smtp)dnl
      MAILER(procmail)dnl

@@ Line 186: / Line 186: @@
 Then, to activate these changes:
 <pre>
 service sendmail restart
 </pre>