[Hampshire] Sendmail authentication and ssl

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Author: Graeme Hilton
Date:  
To: Hampshire LUG Discussion List
Subject: [Hampshire] Sendmail authentication and ssl
Hi,

I run sendmail on my home server. It's not internet facing and only
accepts connections from within my home network. However, I would like
it to accept connections from external mail clients, such as my mobile
phone. Preferably this would be over an encrypted link. I already run
IMAPS for retreiving mail.

My problem is deciphering the sendmail configuration. I have no idea
what the guy who wrote it was thinking, but it's just a horrendous mess
of crap!!!

Below is my sendmail.mc file as it currently stands. Basically I have
managed to send an email from my mobile phone, using the SSL option.
However, I'm not entirely sure that the system is doing what I think
it's doing. Can someone just confirm that I've not set up an open
relay, and that things look ok with this setup?

Secondly, I use Horde as a webmail solution for my family. It seems
that since I changed sendmails settings no outgoing mail is being sent
from Horde. I think it's probably the self-signed certificates that
sendmail is using that is tripping up Horde. I've had a look through
some documentation for Horde, but nothing stands out as relating to
SMTPS. Any Horde users here that might know better?

Thanks.

--
Graeme Hilton


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
EXPOSED_USER(`root')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
DAEMON_OPTIONS(`Port=smtp,Addr=192.168.0.102, Name=MTA')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 #
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 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(`fishter.org.uk')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 #
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