I use blacklists on my sendmail 8.12 server. I use 19 blacklists. I reject all mail from dialup and dsl addresses, open relays, and habitual spammers. I block around 500-700 spam a day. And get around 500-1500 email messages going through the system per day. I get around 1 false positive every 2 weeks. The best part is I don't have to do anything, to keep it working... On the reject messege I refer people to a webpage that gives them an address they can use to bypass the spam filters, or contact me. If you have an entry like this in your /etc/mail/access file, any mail sent to username+WHATEVEREXTENSIONYOUPICK@yourdomain.com Bypasses any spam checking, and is delivered to username@yourdomain.com Sample access entry: #acecepts mail for any usernme+WHATEVEREXTENSIONYOUPIC@yourdomain.com and routes to username@yourdomain.com without doing spam checking. Spam:me+--@ FRIEND #reject his domain optinamerica.net REJECT # old user reject all mail for joebob@ ERROR:550 Mailbox disabled for this recipient #no spam checking is done for this person Spam:iwantspam FRIEND #all mail for postmaster is accepted Spam:postmaster FRIEND ------------------ I would recommend upgrading from 8.11 to 8.12 if you are using dnbl lists. As it allows timeout on dnsbl lookouts, without rejecting the email. I configured these options to block spam: define(`confPRIVACY_FLAGS', `noexpn noreceipts authwarnings noetrn') dnl some mail servers don't give expn or helo dnl define(`confPRIVACY_FLAGS', `needmailhelo needexpnhelo noexpn needvrfyhelo noreceipts authwarnings n oetrn noverb') dnl 1.6 meg limit on message size define(`confMAX_MESSAGE_SIZE',1600000)dnl dnl timeout on the initial outgoing connect define(`TimoutIconnect=30s')dnl define(`confLOG_LEVEL',`14')dnl dnl I can do a dns lookup on hte mailer, EVERY MAILER should be be able to do this. define(`_IP_LOOKUP_',1)dnl dnl mailers that don't have a reverse lookup host-ip won't pass this. define(`_DNSVALID_',1)dnl dnl here is the default header in sendmail:$j Sendmail $v/$Z; $b dnl I change it to remove version information. define(`confSMTP_LOGIN_MSG',$j Sendmail; $b)dnl dnl this will wait 2 minutes for a command from the other mailer. dnl this will timeout on mailers that are parasiting on my mailer. dnl this has never caused problems on mail delivery, it just removes troublesome dnl mailers (spammers that won't resolve ip or similar.) define(`confTO_COMMAND',120s)dnl dnl timeout on the initial outgoing connect define(`ConnectionCacheTimeout=30')dnl FEATURE(enhdnsbl,`bl.spamcop.net',`',`t',`Spam blocked see: http://spamcop.net/bl.shtml?$&{client_addr}Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`relays.osirusoft.com',`',`t',`Spam blocked see: http://relays.osirusoft.com Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl, `relays.ordb.org',`',`t',`Spam blocked - see http://ordb.org/ Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`relays.visi.com',`', `t',`Spam blocked see: http://relays.visi.com Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`blackholes.mail-abuse.org', `t',`Spam blocked see: http://www.mail-abuse.org/rbl/ Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl, `relays.mail-abuse.org', `t',`Spam blocked see: http://www.mail-abuse.org/rss/ Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`dialups.mail-abuse.org', `t',`Spam blocked see: http://www.mail-abuse.org/dul/ Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`rbl-plus.mail-abuse.org', `t',`Spam blocked see: http://www.mail-abuse.org/ Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`blackhole.compu.net', `t',`Spam blocked see: http://www.compu.net Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`pm0-no-more.compu.net', `t',`Spam blocked see: http://www.compu.net Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`flowgoaway.com', `t',`Spam blocked see: Blocked FLOW network systems Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`spamguard.leadmon.net', `t',`Spam blocked see: http://www.leadmon.net/spamguard Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`blackholes.intersil.net', `t',`Spam blocked see: http://www.intersil.net Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`blackholes.wirehub.net', `t',`Spam blocked see: http://basic.wirehub.nl/blackholes.html Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`dynablock.wirehub.net', `t',`Spam blocked see: http://basic.wirehub.nl/dynablocker.htm Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`dsn.rfc-ignorant.org', `t',`Spam blocked see: http://www.rfc-ignorant.org Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`postmaster.rfc-ignorant.org', `t',`Spam blocked see: http://www.rfc-ignorant.org Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`abuse.rfc-ignorant.org', `t',`Spam blocked see: http://www.rfc-ignorant.org Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl FEATURE(enhdnsbl,`in.dnsbl.org', `t',`Spam blocked see: http://www.dnsbl.org Contact postmaster@cs.montana.edu with problems. Read http://www.cs.montana.edu/faq/spam.htm for help')dnl > --Luke > --Computer Science Sysadmin, MSU Bozeman > --admin(AT)cs.montana.edu 994-3931 > -----Original Message----- > From: psyche-list-admin@redhat.com [mailto:psyche-list-admin@redhat.com] > On Behalf Of Gregory L. Hering > Sent: Wednesday, January 22, 2003 9:51 AM > To: psyche-list@redhat.com > Subject: Re: Anti-spam > > ...mmm sorry about the HTML...! > > Yes, blocking China would help. .cn, .ru, .cz, .br, ... how about > everything? > > Better, why not make it like importing goods. Nobody gets in without a > permit. Nobody gets to keep their permit if they are sending spam. The > burden shifts to the ISPs, but it also puts a huge burden on the users > because until their ISPs care, their e-mail is blocked. They will > probably > just block our e-mails because we blocked their e-mails and it becomes a > stalemate. It really is a wild frontier and it gets abused because it's > so > easy to abuse. > > The question for this group is: Is there anything that we, collectively, > as > Red Hat admins and developers, can do about the problem? > > Greg > > > > > -- > Psyche-list mailing list > Psyche-list@redhat.com > https://listman.redhat.com/mailman/listinfo/psyche-list -- Psyche-list mailing list Psyche-list@redhat.com https://listman.redhat.com/mailman/listinfo/psyche-list
