Fedora 15

By default, sendmail can not relay email for other computers. To enable the email relay for a specific computer, you can edit the /etc/mail/access file. For a roaming user, this configuration does not work because the client IP address is unpredictable. The best way is to bind a certificate to sendmail. The define(`confAUTH_OPTIONS', `A p y')dnl line will relay email unless the client is authenticated with a plain text password on TLS connection. To enable TLS connection, a certificate binding must be configured.

define(`confCACERT_PATH', `/etc/pki/tls/certs')dnl
define(`confCACERT', `/etc/pki/tls/certs/ca-bundle.crt')dnl
define(`confSERVER_CERT', `/etc/pki/tls/certs/sendmail.pem')dnl
define(`confSERVER_KEY', `/etc/pki/tls/certs/sendmail.pem')dnl

define(`confAUTH_OPTIONS', `A p y')dnl

DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl
DAEMON_OPTIONS(`Port=smtps, Name=MTA')dnl

TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl

Based on the above settings

Run the command to create a dummy certificate:sendmail.pem

/etc/pki/tls/certs/make sendmail.pem

 

chkconfig saslauthd on

/sbin/service saslauthd start

/sbin/service sendmail restart

turn off firewall for testing

chkconfig iptables off

chkconfig ip6tables off

/sbin/service iptables stop

/sbin/service ip6tables stop

Thunderbird client configuration

SMTP Server name:mail.iamtraining.com
Port:25
Connection security:STARTTLS
Authentication Method:Normal password
User Name:kaiming

Then, thunderbird on another computer can send email out.

Outlook client configuration

My outgoing server server (SMTP) requires authentication must be checked.

Server Port Number

Outgoing server (SMTP): 25
Use the following type of encrypted connection:TLS

/etc/mail/access

Connect:localhost.localdomain           RELAY
Connect:localhost                       RELAY
Connect:127.0.0.1                       RELAY

/etc/mail/sendmail.mc

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 #     /etc/mail/make
dnl #
include(`/usr/share/sendmail-cf/m4/cf.m4')dnl
VERSIONID(`setup for linux')dnl
OSTYPE(`linux')dnl
dnl #
dnl # Do not advertize sendmail version.
dnl #
dnl define(`confSMTP_LOGIN_MSG', `$j Sendmail; $b')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 #
dnl define(`SMART_HOST', `smtp.your.provider')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 #
define(`confAUTH_OPTIONS', `A p y')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 #
TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')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 /etc/pki/tls/certs; make sendmail.pem
dnl # Complete usage:
dnl #     make -C /etc/pki/tls/certs usage
dnl #
define(`confCACERT_PATH', `/etc/pki/tls/certs')dnl
define(`confCACERT', `/etc/pki/tls/certs/ca-bundle.crt')dnl
define(`confSERVER_CERT', `/etc/pki/tls/certs/sendmail.pem')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 # If you're operating in a DSCP/RFC-4594 environment with QoS
dnl define(`confINET_QOS', `AF11')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 20.) sendmail refuses
dnl # to accept connections once it has reached its quota of child processes.
dnl #
dnl define(`confMAX_DAEMON_CHILDREN', `20')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
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, Name=MTA')dnl
DAEMON_OPTIONS(`Port=smtps, 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
LOCAL_DOMAIN(`iamtraining.com')dnl
LOCAL_DOMAIN(`1ask2.com')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 #
dnl MASQUERADE_AS(`mydomain.com')dnl
dnl #
dnl # masquerade not just the headers, but the envelope as well
dnl #
dnl FEATURE(masquerade_envelope)dnl
dnl #
dnl # masquerade not just @mydomainalias.com, but @*.mydomainalias.com as well
dnl #
dnl FEATURE(masquerade_entire_domain)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

DAEMON_OPTIONS(`Port=smtps, Name=MTA')dnl

The above line will make the sendmail listening on 465 port.

Using the Godaddy certificate

public key of vanarts.com

/etc/pki/tls/certs/vanarts.crt

private key of vanarts.com

/etc/pki/tls/certs/vanarts.key

Goddady certificate
/etc/pki/tls/certs/gd_bundle.crt



You must set up the permissions as follows:



chmod 600 /etc/pki/tls/certs/vanarts.crt
chmod 600 /etc/pki/tls/certs/gd_bundle.crt
chmod 600 /etc/pki/tls/private/vanarts.key

If you don't, /var/log/maillog will record the error message:

Aug  6 02:01:23 mail sendmail[8152]: STARTTLS=server: file /etc/pki/tls/certs/vanarts.crt unsafe: Group readable file


From telnet localhost 25, the starttls authentication will not be listed.

Put the godaddy certificate into /certs directory instead of /etc/pki/tls directory

For certificate in /certs, chmod 600 /certs/* must be run.

/etc/mail/sendmail.mc

define(`confCACERT_PATH', `/certs')dnl
define(`confCACERT', `/certs/gd_bundle.crt')dnl
define(`confSERVER_CERT', `/certs/vanarts.crt')dnl
define(`confSERVER_KEY', `/certs/vanarts.key')dnl

/etc/httpd/conf.d/ssl.conf

SSLCertificateFile /certs/vanarts.crt

SSLCertificateKeyFile /certs/vanarts.key

SSLCertificateChainFile /certs/gd_bundle.crt

I have to turn off Seliux to start httpd.

setenforce 0

If not, the httpd daemon failed to start. The following message is recorded in /var/log/messages.

SELinux is preventing /usr/sbin/httpd from getattr access on the file /certs/vanarts.crt.

If SELinux is enabled, you can download system-config-selinux tool.


yum install setools-console

system-config-selinux

File Labeling
Add

File Specification: /certs/.*
Selinux File Type: cert_t:s0
File Type: all files

Status:
Select "Relabel on next reboot"

Reboot the system

The httpd daemon starts with the certificate located in /certs directory.