https://kb.rvmgroup.it/index.php?action=history&feed=atom&title=Migliorare_la_configurazione_antispam_di_postfix 2026-05-10T04:12:47Z Revision history for this page on the wiki MediaWiki 1.44.2 https://kb.rvmgroup.it/index.php?title=Migliorare_la_configurazione_antispam_di_postfix&diff=7314&oldid=prev 2010-11-05T08:04:38Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 08:04, 5 November 2010</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Stub}}</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Stub}}</div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Riferimenti da Verificare==</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* [http://www200.pair.com/mecham/spam/additional_settings_v2.html Additional Anti-UCE settings]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* [http://www.ebb.org/bkuhn/blog/2008/01/09/postfix-secondary-mx-local-deliver.html Postfix Trick to Force Secondary MX to Deliver Locally]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* [http://www.freespamfilter.org/FC4.html How to install Postfix, Amavisd-new, SpamAssassin, Pyzor, Rzor, DCC, and ClamAV on Fedora Core 4 v2.1.8]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">*[http://doc.sumy.ua/network/postfix/faq.html#virtual_setup Postfix Frequently Asked Questions]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">*[http://www.postfix.org/ADDRESS_VERIFICATION_README.html Postfix Address Verification]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">*[http://doc.sumy.ua/network/postfix/faq.html Postfix Frequently Asked Questions:Postfix accepts mail for non-existing local users]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">*[http://www200.pair.com/mecham/spam/amavisd-settings.html Amavisd-new critical settings]</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt</ins></div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add</div></td></tr> </table>

Gabriele.vivinetto https://kb.rvmgroup.it/index.php?title=Migliorare_la_configurazione_antispam_di_postfix&diff=5673&oldid=prev 2008-04-01T13:44:54Z

<p>New page: {{Stub}} Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add following directives to /etc/postfix/main.cf file: *=&gt; disable_vrfy_command = y...</p> <p><b>New page</b></p><div>{{Stub}}<br /> <br /> Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add<br /> following directives to /etc/postfix/main.cf file:<br /> <br /> *=&gt; disable_vrfy_command = yes : Disable the SMTP VRFY command. This stops some techniques used to harvest email addresses.<br /> <br /> *=&gt; smtpd_delay_reject = yes : It allows Postfix to log recipient address information when rejecting a client name/address or sender address, so that it is possible to find out whose mail is being rejected.<br /> <br /> *=&gt; smtpd_helo_required = yes : Require that a remote SMTP client introduces itself at the beginning of an SMTP session with the HELO or EHLO command. Many spam bot ignores HELO/EHLO command and you save yourself from spam. <br /> <br /> Following lines further restrictions on HELO command:<br /> *smtpd_helo_restrictions = permit_mynetworks,<br /> *reject_non_fqdn_hostname, Reject email if remote hostname is not in fully-qualified domain form. Usually bots *sending email don’t have FQDN names.<br /> *reject_invalid_hostname, Reject all bots sending email from computers connected via DSL/ADSL computers. They don’t have valid internet hostname.<br /> <br /> You can put the following access restrictions that the Postfix SMTP server applies in the context of the RCPT TO command.<br /> *=&gt; smtpd_recipient_restrictions =<br /> reject_invalid_hostname, - Reject email if it not valid hostname<br /> reject_non_fqdn_hostname, - Reject email if it not valid FQDN<br /> reject_non_fqdn_sender, - Reject the request when the MAIL FROM address is not in fully-qualified domain form. For example email send from xyz or abc is rejected.<br /> reject_non_fqdn_recipient, - Reject the request when the RCPT TO address is not in fully-qualified domain form<br /> reject_unknown_sender_domain, - Reject email, if sender domain does not exists<br /> reject_unknown_recipient_domain, Reject email, if recipient domain does not exists<br /> permit_mynetworks,<br /> reject_rbl_client list.dsbl.org, Configure spam black lists<br /> reject_rbl_client sbl.spamhaus.org,<br /> reject_rbl_client cbl.abuseat.org,<br /> reject_rbl_client dul.dnsbl.sorbs.net<br /> <br /> Open /etc/postfix/main.cf file :<br /> # vi /etc/postfix/main.cf<br /> Set/modify configuration as follows<br /> <br /> disable_vrfy_command = yes<br /> smtpd_delay_reject = yes<br /> smtpd_helo_required = yes<br /> smtpd_helo_restrictions = permit_mynetworks,<br /> reject_non_fqdn_hostname,<br /> reject_invalid_hostname,<br /> permit<br /> <br /> smtpd_recipient_restrictions =<br /> permit_sasl_authenticated,<br /> reject_invalid_hostname,<br /> reject_non_fqdn_hostname,<br /> reject_non_fqdn_sender,<br /> reject_non_fqdn_recipient,<br /> reject_unknown_sender_domain,<br /> reject_unknown_recipient_domain,<br /> permit_mynetworks,<br /> reject_rbl_client list.dsbl.org,<br /> reject_rbl_client sbl.spamhaus.org,<br /> reject_rbl_client cbl.abuseat.org,<br /> reject_rbl_client dul.dnsbl.sorbs.net,<br /> permit<br /> <br /> smtpd_error_sleep_time = 1s<br /> smtpd_soft_error_limit = 10<br /> smtpd_hard_error_limit = 20<br /> <br /> Also force (highlighted using red color) Postfix to limit incoming or receiving email rate to avoid spam.<br /> <br /> Save and close the file. Restart postfix:<br /> # /etc/init.d/postfix restart<br /> <br /> Watch out maillog file. Now you should see lots of spam email blocked by above configuration directive:<br /> # tail -f /var/log/maillog<br /> Output:<br /> <br /> &lt;pre&gt;<br /> Jan 9 06:07:22 server postfix/smtpd[10308]: NOQUEUE: reject: RCPT from 183-12-81.ip.adsl.hu[81.183.12.81]: 554 Service unavailable; Client host [81.183.12.81] blocked using dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?81.183.12.81; from= to= proto=ESMTP helo=&lt;183-12-230.ip.adsl.hu&gt;<br /> Jan 9 06:07:23 server postfix/smtpd[10308]: lost connection after RCPT from 183-12-81.ip.adsl.hu[81.183.12.81]<br /> Jan 9 06:07:23 server postfix/smtpd[10308]: disconnect from 183-12-81.ip.adsl.hu[81.183.12.81]<br /> Jan 9 06:10:43 server postfix/anvil[10310]: statistics: max connection rate 1/60s for (smtp:81.183.12.81) at Jan 9 06:07:17<br /> Jan 9 06:10:43 server postfix/anvil[10310]: statistics: max connection count 1 for (smtp:81.183.12.81) at Jan 9 06:07:17<br /> Jan 9 06:10:43 server postfix/anvil[10310]: statistics: max cache size 1 at Jan 9 06:07:17<br /> Jan 9 06:16:58 server postfix/smtpd[10358]: warning: 81.92.197.249: address not listed for hostname unassigned.or.unconfigured.reverse.nfsi-telecom.net<br /> Jan 9 06:16:58 server postfix/smtpd[10358]: connect from unknown[81.92.197.249]<br /> Jan 9 06:17:00 server postfix/smtpd[10358]: NOQUEUE: reject: RCPT from unknown[81.92.197.249]: 550 : Recipient address rejected: User unknown in virtual alias table; from=&lt;&gt; to= proto=ESMTP helo=<br /> Jan 9 06:17:00 server postfix/smtpd[10358]: disconnect from unknown[81.92.197.249]<br /> &lt;/pre&gt;<br /> <br /> Next time I will write about simple procmail and spamassassin combination to filter out spam :)<br /> <br /> Want to stay up to date with the latest Linux tips, news and announcements? Subscribe to our free e-mail newsletter or full RSS feed to get all updates. You can Email this page to a friend. <br /> <br /> ==Riferimenti==<br /> *[http://www.cyberciti.biz/tips/postfix-spam-filtering-with-blacklists-howto.html Postfix configure anti spam with blacklist]</div>

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