update spam countermeasures
add examples of using an access_db
update .mc files to match recommendations on
http://www.sendmail.org/m4/anti-spam.html
(grrr.....should have been one commit
did the last commit from a subdirectory)
This commit is contained in:
Jonathan M. Bresler
parent
54919b86a0
commit
762003080e
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=46959
@ -1,13 +1,6 @@
|
||||
# $Id: Makefile,v 1.5 1998/09/13 23:14:20 brian Exp $
|
||||
# $Id: Makefile,v 1.6 1999/01/31 15:21:15 jmb Exp $
|
||||
|
||||
install:
|
||||
/usr/sbin/makemap hash /etc/mail/spamsites < /etc/mail/block_domains.txt
|
||||
.if exists(/etc/mail/spamsites.local)
|
||||
/usr/sbin/makemap -o hash /etc/mail/spamsites < /etc/mail/spamsites.local
|
||||
.endif
|
||||
/usr/sbin/makemap hash /etc/mail/denyip < /etc/mail/block_ips.txt
|
||||
.if exists(/etc/mail/denyip.local)
|
||||
/usr/sbin/makemap -o hash /etc/mail/denyip < /etc/mail/denyip.local
|
||||
.endif
|
||||
/usr/sbin/makemap hash /etc/mail/access < /etc/mail/access.txt
|
||||
|
||||
all: install
|
||||
|
||||
@ -1,74 +1,17 @@
|
||||
# $Id: README,v 1.5 1998/09/02 01:34:57 brian Exp $
|
||||
# $Id: README,v 1.5.2.1 1999/05/01 03:37:29 jkh Exp $
|
||||
|
||||
Filtering out SPAM from your site
|
||||
Sendmail now includes excellent tools block spam. These
|
||||
tools are available as FEATUREs that you can add to your site's
|
||||
.mc file. Proper use of these FEATUREs will prevent spammer from
|
||||
using your site as a relay as well as significantly decrease the
|
||||
amount of spam that arrives at your site. No set of anti-spam
|
||||
tools will block all spam without blocking some portion of legitimate
|
||||
mail as well. Therefore, these FEATUREs are designed to prevent
|
||||
as much spam as possible without blocking legitimate mail.
|
||||
|
||||
Introduction:
|
||||
The FreeBSD Project filters spam, unsolicited commerical
|
||||
e-mail, from its mailing lists. The filter has two parts: databases
|
||||
and rulesets. We have rulesets to /etc/sendmail.cf, check_rcpt,
|
||||
check_relay, check_rbl, check_mail and xlat. (xlat is for testing
|
||||
only, as explained in /etc/mail/sendmail.cf.additions.) These
|
||||
rulesets use three databases. The denyip, a list of IP addresses,
|
||||
spamsites, a list of domains, and fakenames, a list of bogus
|
||||
usernames (such as investor and success). We do not accept mail
|
||||
from any machine that matches a entry in either database, or users
|
||||
in the fakenames database.
|
||||
These tools are discussed in /usr/src/contrib/sendmail/cf/README.
|
||||
Read the section entitled "ANTI-SPAM CONFIGURATION CONTROL". Example
|
||||
usage and additional tools can be found in
|
||||
/usr/src/contrib/sendmail/cf/cf/knecht.mc.
|
||||
|
||||
Filtering at your site:
|
||||
To filter spam at your site you need to:
|
||||
1. modify your /etc/sendmail.cf,
|
||||
2. create a list of domains/ips you wish to block
|
||||
3. make the databases and
|
||||
4. finally signal sendmail that the configuration file has changed.
|
||||
|
||||
1. Modifying your /etc/sendmail.cf
|
||||
Add the database declarations and the rulesets contained
|
||||
in /etc/mail/sendmail.cf.additions to your .mc file. If you do
|
||||
not use m4 to generate your /etc/sendmail.cf, add the database
|
||||
declarations to your /etc/sendmail.cf.
|
||||
|
||||
2. Put the list of domains you wish to block in /etc/mail/spamsites
|
||||
|
||||
3. Make the databases:
|
||||
As root, type "cd /etc/mail; make install" will build the
|
||||
two databases from the retrieved source files and the local additions
|
||||
files.
|
||||
|
||||
4. Signaling sendmail:
|
||||
Sendmail will reread its configuration whenever sendmail
|
||||
receives a HUP signal. As root, type "kill -HUP `cat
|
||||
/var/run/sendmail.pid`". Check sendmail's log file to be sure that
|
||||
it has restarted. /var/log/maillog should contain the line: "Oct
|
||||
15 08:59:16 hub sendmail[6565]: restarting /usr/sbin/sendmail on
|
||||
signal". Most likely, the date, time, hostname and process id will
|
||||
be differ.
|
||||
|
||||
Testing the spam filter:
|
||||
|
||||
How can I tell if its working:
|
||||
The mail log file, /var/log/maillog, will contain a line
|
||||
for every message filtered. The lines will be similar to one of
|
||||
these two log entries:
|
||||
|
||||
Check_mail rejects:
|
||||
Oct 15 02:43:26 hub sendmail[6565]: CAA06565: ruleset=check_mail,
|
||||
arg1=<announce@martianconsulate.com>, relay=xxx.isp.net [###.###.###.###],
|
||||
reject=521 <announce@martianconsulate.com>
|
||||
|
||||
Nov 30 15:56:37 hub sendmail[15058]: PAA15058: ruleset=check_mail,
|
||||
arg1=<ultramax@s2.eddelwissl.NET>, relay=relay.somewhere.com
|
||||
[###.###.###.###], reject=451 <ultramax@s2.eddelwissl.NET>... Domain
|
||||
does not resolve
|
||||
|
||||
|
||||
Check_relay rejects:
|
||||
Oct 19 04:45:24 hub sendmail[3503]: NOQUEUE: ruleset=check_relay,
|
||||
arg1=imsp015.netvigator.com, arg2=205.252.144.206, relay=root@localhost,
|
||||
reject=521 blocked.contact postmaster@FreeBSD.ORG
|
||||
|
||||
check_rcpt reject:
|
||||
Nov 30 15:04:08 hub sendmail[12390]: PAA12390: ruleset=check_rcpt,
|
||||
arg1=investor@100percent.per.year.com, relay=newfed.frb.gov
|
||||
[198.3.221.5], reject=553 investor@100percent.per.year.com...
|
||||
521<investor@100percent.per.year.com>#blocked.contact postmaster
|
||||
Sun Nov 16 11:40:53 PST 1997
|
||||
|
||||
@ -1,125 +0,0 @@
|
||||
# $Id:$
|
||||
#
|
||||
# list of hosts and domains for whom we relay mail.
|
||||
# all .forward hosts, domains must be listed in this file.
|
||||
# same for hosts and domains in /etc/aliases
|
||||
F{LocalIP}-o /etc/mail/Local-IP
|
||||
F{RelayTo}-o /etc/mail/Relay-Hosts
|
||||
|
||||
# database declarations
|
||||
Kdenyip hash -o -a.REJECT /etc/mail/denyip.db
|
||||
Kfakenames hash -o -a.REJECT /etc/mail/fakenames.db
|
||||
Kspamsites hash -o -a.REJECT /etc/mail/spamsites.db
|
||||
|
||||
# helper rulsesets; useful for debugging sendmail configurations
|
||||
#
|
||||
#
|
||||
Scheck_rbl
|
||||
# lookup up an ip address in the Realtime Blackhole List.
|
||||
R$-.$-.$-.$- $: $(host $4.$3.$2.$1.rbl.maps.vix.com $:OK $)
|
||||
|
||||
Sxlat # for sendmail -bt
|
||||
# sendmail treats "$" and "|" as two distinct tokens
|
||||
# this rule "pastes" them together into one token
|
||||
# and then calls check_relay.
|
||||
R$* $$| $* $: $1 $| $2
|
||||
R$* $| $* $@ $>check_relay $1 $| $2
|
||||
|
||||
Scheck_relay
|
||||
# called with "hostname.tld $| IP address" of connecting host.
|
||||
# hostname.tld is the fully-qualified domain name
|
||||
# IP address is dotted-quad with surrounding "[]" brackets.
|
||||
#
|
||||
# each group of rules in this ruleset is independent.
|
||||
# each accepts and return "hostname.tld $| IP address"
|
||||
# use the ones that you want comment out the rest
|
||||
# you may rearrange the groups but not the rules in each group.
|
||||
# each group is preceded and followed by a comment
|
||||
#
|
||||
# host must NOT be in the "spamsites" database--BEGIN
|
||||
R$* $| $* $: <$1 $| $2> $1
|
||||
R<$*> $+.$+.$+ <$1> $3.$4
|
||||
R<$*> $+.$+ $: <$1> $(spamsites $2.$3 $)
|
||||
R<$*> $*.REJECT $#error $: 521 blocked. contact postmaster@$m
|
||||
R<$*> $* $: $1
|
||||
# host must NOT be in the "spamsites" database--END
|
||||
# ip address must NOT be in the "denyip" database--BEGIN
|
||||
R$* $| $* $: $1 $| $(denyip $2 $)
|
||||
R$* $| $*.REJECT $#error $: 521 blocked. contact postmaster@$m
|
||||
# ip address must NOT be in the "denyip" database--END
|
||||
R$* $@ OK
|
||||
|
||||
Scheck_mail
|
||||
# called with envelope sender (everything after ":") in
|
||||
# "Mail From: xxx", of SMTP conversation
|
||||
# may or may not have "<" ">"
|
||||
# the groups of rules in this ruleset ARE NOT independent.
|
||||
# "remove all RFC-822 comments" must come first
|
||||
# "Connecting Host" and "Paul Vixie's RBL" must be last
|
||||
#
|
||||
# use the ones that you want comment out the rest
|
||||
# each group is preceded and followed by a comment
|
||||
#
|
||||
# remove all RFC-822 comments--BEGIN
|
||||
# MUST be first rule in check_mail rulseset.
|
||||
R$* $: $>3 $1
|
||||
# remove all RFC-822 comments--END
|
||||
# mail must come from a DNS resolvable host--BEGIN
|
||||
R$* < @ $+ . > $: $1 @ $2
|
||||
R$* < @ $+ > $#error $@ 4.1.8 $: "451 Domain does not resolve"
|
||||
# mail must come from a DNS resolvable host--END
|
||||
# mail must NOT come from a known source of spam--BEGIN
|
||||
R$+ @$+ $: <$1@$2> $2
|
||||
R<$*> $+.$+.$+ <$1> $3.$4
|
||||
R<$*> $* $: $(spamsites $2 $: OK $)
|
||||
R$+.REJECT $#error $@ 5.7.1 $: 550 $1
|
||||
R<$*> $* $: $1
|
||||
# mail must NOT come from a known source of spam--END
|
||||
# Connecting Host must resolve--BEGIN
|
||||
R$* $: $1 $: $(dequote "" $&{client_name} $)
|
||||
R$* $: $>3 foo@$1
|
||||
R<$*> $*<@$*> $#error $@ 4.1.8 $: "451 Domain does not resolve"
|
||||
# Connecting Host must resolve--END
|
||||
# ip address must NOT be in Paul Vixie's RBL--BEGIN
|
||||
R$* $: $1 $: $(dequote "" $&{client_addr} $)
|
||||
R$* $: $>check_rbl $1
|
||||
R$*.com. $#error $@ 5.7.1 $: "550 Mail refused, see http://maps.vix.com/rbl"
|
||||
# ip address must NOT be in Paul Vixie's RBL--END
|
||||
R$* $@ OK
|
||||
|
||||
Scheck_rcpt
|
||||
# called with envelope recipient (everything after ":") in
|
||||
# "Rcpt To: xxx", of SMTP conversation
|
||||
# may or may not have "<" ">" and or RFC-822 comments.
|
||||
# let ruleset 3 clean this up for us.
|
||||
#
|
||||
# do NOT reorder these two groups of rules.
|
||||
# restrict mail relaying to host and domains listed in /etc/sendmail.cR
|
||||
#
|
||||
# mail must NOT be addressed "fakenames"--BEGIN
|
||||
R$* $: <$1> $>3 $1
|
||||
R<$*> $+ < @ $+ > $: <$1> $(fakenames $2 $: OK $)
|
||||
R$+.REJECT $#error $@ 5.2.1 $: 550 $1
|
||||
R<$*> $* $: $1
|
||||
# mail must NOT be addressed "fakenames"--END
|
||||
# mail must come from or go to this machine or machines we allow to relay--BEGIN
|
||||
# from http://www.informatik.uni-kiel.de/%7Eca/email/check.html#check_rcpt
|
||||
R$+ $: $(dequote "" $&{client_addr} $) $| $1
|
||||
R0 $| $* $@ ok
|
||||
R$={LocalIP}$* $| $* $@ ok
|
||||
# not local, check rcpt
|
||||
R$* $| $* $: $>3 $2
|
||||
# remove local part, maybe repeatedly
|
||||
R$+ $:$>removelocal $1
|
||||
# still something left?
|
||||
R$*<@$+>$* $#error $@ 5.7.1 $: 550 we do not relay
|
||||
#
|
||||
Sremovelocal
|
||||
# remove RelayTo part (maybe repeatedly)
|
||||
# R$*<@$*$={RelayTo}.>$* $>3 $1 $4
|
||||
R$*<@$=w.>$* $: $>removelocal $>3 $1 $3
|
||||
R$*<@$*>$* $@ $1<@$2>$3
|
||||
# dequote local part
|
||||
R$- $: $>3 $(dequote $1 $)
|
||||
R$*<@$*>$* $: $>removelocal $1<@$2>$3
|
||||
# mail must come from or go to this machine or machines we allow to relay--END
|
||||
Loading…
Reference in New Issue
Block a user