I have (2) Red Hat 9 boxes that I am running various services on. One of these boxes is running Sendmail as an MTA. I have the box setup to query about 10 DNS Blacklists upon each incoming e-mail. A friend of mine just signed up with Yahoo to do their e-mail hosting. Now everytime he sends me a message, one of the blacklists reject the message because Yahoo's business mail servers are on the particular black list. There are also some other important people that cannot email anyone on our domain because their e-mail servers (AOL, Yahoo, etc) are blacklisted. I am not willing to take the particular BlackLists out of the picture because they are well known ones and block probably about 75% of the "real spam" that attempts to make its way through. I did some research and found out I could modify the /etc/mail/access file to enter permissible domains, IP blocks, and individual e-mail addresses. I tried adding the individual e-mail addresses that I would like to allow e-mail from, but this is not working. Here are the formats I have tried: friend@friend.com OK friend@friend.com RELAY From:friend@friend.com OK Neither of these allow the message to come through. The /etc/mail/sendmail.mc file seems to be taking precedence over the /etc/mail/access file. Through troubleshooting I was able to determine that the /etc/mail/access file IS indeed being looked at. I added my yahoo email address as a rejected sender and Sendmail did block it, specifically stating in the logs that it was because I had it set to do so in the access file. Is there some setting in the sendmail.mc file that I am missing? Everytime I change the settings I issue "make all" followed by "service sendmail restart. Below is a copy of my sendmail.mc file: 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 # 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 # define(`confDEF_USER_ID',``8:12'')dnl define(`confTRUSTED_USER', `smmsp')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 dnl define(`STATUS_FILE', `/etc/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 # 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 # make -C /usr/share/ssl/certs usage dnl # dnl define(`confCACERT_PATH',`/usr/share/ssl/certs') dnl define(`confCACERT',`/usr/share/ssl/certs/ca-bundle.crt') dnl define(`confSERVER_CERT',`/usr/share/ssl/certs/sendmail.pem') dnl define(`confSERVER_KEY',`/usr/share/ssl/certs/sendmail.pem') 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 -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 # 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 # NOTE: binding both IPv4 and IPv6 daemon to the same port requires dnl # a kernel patch dnl # dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')dnl 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 # 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 # 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 FEATURE(`dnsbl', `sbl.spamhaus.org', `"Rejected: sbl.spamhaus.org"')dnl FEATURE(`dnsbl', `relays.ordb.org', `"Rejected: relays.ordb.org"')dnl FEATURE(`dnsbl', `opm.blitzed.org', `"Rejected: opm.blitzed.org"')dnl FEATURE(`dnsbl', `dialups.visi.com', `"Rejected: dialups.visi.com"')dnl FEATURE(`dnsbl', `relays.visi.com', `"Rejected: relays.visi.com"')dnl FEATURE(`dnsbl', `xbl.spamhaus.org', `"Rejected: xbl.spamhaus.org"')dnl FEATURE(`dnsbl', `bl.spamcop.net', `"Rejected: bl.spamcop.net"')dnl FEATURE(`dnsbl', `list.dsbl.org', `"Rejected: list.dsbl.org"')dnl FEATURE(`dnsbl', `multihop.dsbl.org', `"Rejected: multihop.dsbl.org"')dnl FEATURE(`dnsbl', `blackholes.mail-abuse.org', `"Rejected: blackholes.mail-abuse.org"')dnl FEATURE(`dnsbl', `relays.mail-abuse.org', `"Rejected: relays.mail-abuse.org"')dnl FEATURE(`dnsbl',`dnsbl.sorbs.net',`"554 Rejected " $&{client_addr} " found in dnsbl.sorbs.net"')dnl FEATURE(dnsbl,`combined.njabl.org',`Message from $&{client_addr} rejected - see http://njabl.org/lookup?$&{client_a... FEATURE(dnsbl, `dnsbl.ahbl.org',`550 Host is on the AHBL - Please see http://www.ahbl.org/tools/lookup.ph... MAILER(smtp)dnl MAILER(procmail)dnl ----- Thanks guys, Matt

These links may be of interest: http://people.freenet.de/slgig/cfre... http://ist.uwaterloo.ca/~dkeenan/do... Personally I use a combination of sendmail and spamassassin (which can also be set up to query online blacklists) which I find works a treat.

Did you consider spamassassin difficult to configure? I have a secondary server that I may install sendmail and spam assassin on just to toy with so i don't interrupt my customers.

Not at all. Once it is in place there is very little configuration required. There was a little "training" time where I had to be careful about false positives but it now seems to be doing very well. Here's a good howto: http://www.falkotimme.com/howtos/sp...