From owner-freebsd-questions@FreeBSD.ORG Sun Apr 8 17:16:32 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 1A93616A401 for ; Sun, 8 Apr 2007 17:16:32 +0000 (UTC) (envelope-from norgaard@locolomo.org) Received: from strange.locolomo.org (97.pool85-48-194.static.orange.es [85.48.194.97]) by mx1.freebsd.org (Postfix) with ESMTP id 3F4E213C45D for ; Sun, 8 Apr 2007 17:16:31 +0000 (UTC) (envelope-from norgaard@locolomo.org) Received: from [10.35.4.65] (65.4-35-10-static.chueca.wifi [10.35.4.65]) by strange.locolomo.org (Postfix) with ESMTP id 2D7D22E024; Sun, 8 Apr 2007 19:16:29 +0200 (CEST) Message-ID: <4619236C.9040407@locolomo.org> Date: Sun, 08 Apr 2007 19:16:28 +0200 From: Erik Norgaard User-Agent: Thunderbird 1.5.0.10 (X11/20070309) MIME-Version: 1.0 To: Angelin Lalev References: <0875b56eeca4d320fd9fa7b0d940fce2@uni-svishtov.bg> In-Reply-To: <0875b56eeca4d320fd9fa7b0d940fce2@uni-svishtov.bg> Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg=sha1; boundary="------------ms000808030003080300030708" Cc: freebsd-questions@freebsd.org Subject: Re: advice on anti-spam tools X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Apr 2007 17:16:32 -0000 This is a cryptographically signed message in MIME format. --------------ms000808030003080300030708 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Angelin Lalev wrote: > Hi List, > > My e-mail server is running the latest spamassassin with all of the blacklist enabled and etc. > but I still receive over 20 spam messages a day ("image" spam mostly). > The situation with other users may be worse. That's why I was thinking about some tool that > 1. store incoming email > 2. send request to the sender of the message, requiring to go to some address and enter the numbers (letters) > from image > 3. if the puzzle is solved in time (week or so) deliver the message, otherwise delete it. > > Is there such tool(s) ? I use grey listing and spamhaus xbl, no spamassasin or content analysis. Apart from grey listing and spamhaus, I block in my firewall IP ranges I have found un trustable, particular China and Korea, and ranges assigned dynamically, and I have some header analysis rules. I get about 2 spam mails a day. The earlier you can reject a message the less resources it takes, see how much you can reject on the envelope rather than data. I have found that many spammers use my servers name or IP in HELO, so I reject that. Also, reject unresolvable domains etc, simple stuff. Really, if you want to effectively address the problems, store all spam, create a spambox for users to forward their spam to. Analyse it every now and then. For example I did this to idenfity IP ranges sending spam. With greylisting, I have found that greylisting 5 minutes will delay mail significantly and some mail will not be delivered. 3 minutes seems better. Cheers, Erik -- Ph: +34.666334818 web: http://www.locolomo.org --------------ms000808030003080300030708 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIK6DCC BXAwggRYoAMCAQICBEVUK6IwDQYJKoZIhvcNAQEFBQAwMTELMAkGA1UEBhMCREsxDDAKBgNV BAoTA1REQzEUMBIGA1UEAxMLVERDIE9DRVMgQ0EwHhcNMDYxMTE1MDgzMTU0WhcNMDgxMTE1 MDkwMTU0WjB1MQswCQYDVQQGEwJESzEpMCcGA1UEChMgSW5nZW4gb3JnYW5pc2F0b3Jpc2sg dGlsa255dG5pbmcxOzAUBgNVBAMUDUVyaWsgTvhyZ2FhcmQwIwYDVQQFExxQSUQ6OTgwMi0y MDAyLTItNTQ0MzY5NzY5MzE1MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC1/K6+GVcF UvoWJpyfhzWbu8qEOB8jU17A0dpmts7RT+ODkYq0lxJCcvvdSXNQQurvYwaPISA+EMRy+rIm rjhoyxhsM9w/XC7gELqkr1XbGt3wR0KLr5ZcRfD4HqrWM1Eh1OYxTXKod6Ox/FAqzDAy91x8 XCZzsHtiBCdgMSYxqwIDAQABo4ICzjCCAsowDgYDVR0PAQH/BAQDAgP4MCsGA1UdEAQkMCKA DzIwMDYxMTE1MDgzMTU0WoEPMjAwODExMTUwOTAxNTRaMIIBNwYDVR0gBIIBLjCCASowggEm BgoqgVCBKQEBAQEDMIIBFjAvBggrBgEFBQcCARYjaHR0cDovL3d3dy5jZXJ0aWZpa2F0LmRr L3JlcG9zaXRvcnkwgeIGCCsGAQUFBwICMIHVMAoWA1REQzADAgEBGoHGRm9yIGFudmVuZGVs c2UgYWYgY2VydGlmaWthdGV0IGfmbGRlciBPQ0VTIHZpbGvlciwgQ1BTIG9nIE9DRVMgQ1As IGRlciBrYW4gaGVudGVzIGZyYSB3d3cuY2VydGlmaWthdC5kay9yZXBvc2l0b3J5LiBCZW3m cmssIGF0IFREQyBlZnRlciB2aWxr5XJlbmUgaGFyIGV0IGJlZ3LmbnNldCBhbnN2YXIgaWZ0 LiBwcm9mZXNzaW9uZWxsZSBwYXJ0ZXIuMEEGCCsGAQUFBwEBBDUwMzAxBggrBgEFBQcwAYYl aHR0cDovL29jc3AuY2VydGlmaWthdC5kay9vY3NwL3N0YXR1czAgBgNVHREEGTAXgRVub3Jn YWFyZEBsb2NvbG9tby5vcmcwgYQGA1UdHwR9MHswS6BJoEekRTBDMQswCQYDVQQGEwJESzEM MAoGA1UEChMDVERDMRQwEgYDVQQDEwtUREMgT0NFUyBDQTEQMA4GA1UEAxMHQ1JMMTU1NzAs oCqgKIYmaHR0cDovL2NybC5vY2VzLmNlcnRpZmlrYXQuZGsvb2Nlcy5jcmwwHwYDVR0jBBgw FoAUYLWF7FZkfhIZJ2cdUBVLc647+RIwHQYDVR0OBBYEFPd+a0ceJ9JmK934UXsB3G0mjv+f MAkGA1UdEwQCMAAwGQYJKoZIhvZ9B0EABAwwChsEVjcuMQMCA6gwDQYJKoZIhvcNAQEFBQAD ggEBAE9KhX+l/ZcnhvGPhHyWnJspyCXSiuqZ+GlgMdcKXtlu8kXsqNzfDe9qSs93++zJS+HT vAW0QgyIxjY1VpgCqgyjU8e2d2D1eSRMDB09WViZk8oZkvOy0Mq3yy//CLSw3gQbXNZF+Yt+ htss+FD+idACVyRBQqlcHuaxjguyzZkK0fGBN5H5nsklDySQCU7X0i3egeIiL7zlV3cjp9KT 12tNG4jfQTaSUzBkz0R+x+Jcdyp6AI9Qg3H1iGDDI58aCTY5ohQBpDsUcLr6U842IACNCeub qDP6nDo5lnMEXwGH/RO8r4supCf5wrNRjqEX/vokUzB5QfDGtmxxZkycaaQwggVwMIIEWKAD AgECAgRFVCuiMA0GCSqGSIb3DQEBBQUAMDExCzAJBgNVBAYTAkRLMQwwCgYDVQQKEwNUREMx FDASBgNVBAMTC1REQyBPQ0VTIENBMB4XDTA2MTExNTA4MzE1NFoXDTA4MTExNTA5MDE1NFow dTELMAkGA1UEBhMCREsxKTAnBgNVBAoTIEluZ2VuIG9yZ2FuaXNhdG9yaXNrIHRpbGtueXRu aW5nMTswFAYDVQQDFA1FcmlrIE74cmdhYXJkMCMGA1UEBRMcUElEOjk4MDItMjAwMi0yLTU0 NDM2OTc2OTMxNTCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAtfyuvhlXBVL6Fiacn4c1 m7vKhDgfI1NewNHaZrbO0U/jg5GKtJcSQnL73UlzUELq72MGjyEgPhDEcvqyJq44aMsYbDPc P1wu4BC6pK9V2xrd8EdCi6+WXEXw+B6q1jNRIdTmMU1yqHejsfxQKswwMvdcfFwmc7B7YgQn YDEmMasCAwEAAaOCAs4wggLKMA4GA1UdDwEB/wQEAwID+DArBgNVHRAEJDAigA8yMDA2MTEx NTA4MzE1NFqBDzIwMDgxMTE1MDkwMTU0WjCCATcGA1UdIASCAS4wggEqMIIBJgYKKoFQgSkB AQEBAzCCARYwLwYIKwYBBQUHAgEWI2h0dHA6Ly93d3cuY2VydGlmaWthdC5kay9yZXBvc2l0 b3J5MIHiBggrBgEFBQcCAjCB1TAKFgNUREMwAwIBARqBxkZvciBhbnZlbmRlbHNlIGFmIGNl cnRpZmlrYXRldCBn5mxkZXIgT0NFUyB2aWxr5XIsIENQUyBvZyBPQ0VTIENQLCBkZXIga2Fu IGhlbnRlcyBmcmEgd3d3LmNlcnRpZmlrYXQuZGsvcmVwb3NpdG9yeS4gQmVt5nJrLCBhdCBU REMgZWZ0ZXIgdmlsa+VyZW5lIGhhciBldCBiZWdy5m5zZXQgYW5zdmFyIGlmdC4gcHJvZmVz c2lvbmVsbGUgcGFydGVyLjBBBggrBgEFBQcBAQQ1MDMwMQYIKwYBBQUHMAGGJWh0dHA6Ly9v Y3NwLmNlcnRpZmlrYXQuZGsvb2NzcC9zdGF0dXMwIAYDVR0RBBkwF4EVbm9yZ2FhcmRAbG9j b2xvbW8ub3JnMIGEBgNVHR8EfTB7MEugSaBHpEUwQzELMAkGA1UEBhMCREsxDDAKBgNVBAoT A1REQzEUMBIGA1UEAxMLVERDIE9DRVMgQ0ExEDAOBgNVBAMTB0NSTDE1NTcwLKAqoCiGJmh0 dHA6Ly9jcmwub2Nlcy5jZXJ0aWZpa2F0LmRrL29jZXMuY3JsMB8GA1UdIwQYMBaAFGC1hexW ZH4SGSdnHVAVS3OuO/kSMB0GA1UdDgQWBBT3fmtHHifSZivd+FF7AdxtJo7/nzAJBgNVHRME AjAAMBkGCSqGSIb2fQdBAAQMMAobBFY3LjEDAgOoMA0GCSqGSIb3DQEBBQUAA4IBAQBPSoV/ pf2XJ4bxj4R8lpybKcgl0orqmfhpYDHXCl7ZbvJF7Kjc3w3vakrPd/vsyUvh07wFtEIMiMY2 NVaYAqoMo1PHtndg9XkkTAwdPVlYmZPKGZLzstDKt8sv/wi0sN4EG1zWRfmLfobbLPhQ/onQ AlckQUKpXB7msY4Lss2ZCtHxgTeR+Z7JJQ8kkAlO19It3oHiIi+85Vd3I6fSk9drTRuI30E2 klMwZM9EfsfiXHcqegCPUINx9YhgwyOfGgk2OaIUAaQ7FHC6+lPONiAAjQnrm6gz+pw6OZZz BF8Bh/0TvK+LLqQn+cKzUY6hF/76JFMweUHwxrZscWZMnGmkMYICKjCCAiYCAQEwOTAxMQsw CQYDVQQGEwJESzEMMAoGA1UEChMDVERDMRQwEgYDVQQDEwtUREMgT0NFUyBDQQIERVQrojAJ BgUrDgMCGgUAoIIBRzAYBgkqhkiG9w0BCQMxCwYJKoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEP Fw0wNzA0MDgxNzE2MjhaMCMGCSqGSIb3DQEJBDEWBBQ5dWK3dHwTW07GxS3cjb/9qXdA7TBI BgkrBgEEAYI3EAQxOzA5MDExCzAJBgNVBAYTAkRLMQwwCgYDVQQKEwNUREMxFDASBgNVBAMT C1REQyBPQ0VTIENBAgRFVCuiMEoGCyqGSIb3DQEJEAILMTugOTAxMQswCQYDVQQGEwJESzEM MAoGA1UEChMDVERDMRQwEgYDVQQDEwtUREMgT0NFUyBDQQIERVQrojBSBgkqhkiG9w0BCQ8x RTBDMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMC BzANBggqhkiG9w0DAgIBKDANBgkqhkiG9w0BAQEFAASBgJO0LtHaNmj950e0XkyrHMuecIEW Eyd+K50BeZx/b9BzEKbxuOI2rZQUVnRPimp9V+TQyQ+0pTSi+OxKvFOD78Blph/o0V19yYXL l1EKmC/y6BfcW3rn6fnBkiOUk8TFpyVOlYh+z7IuLIKmQS8h2aX9ArZ+IxDtlVbs5qOyCQXm AAAAAAAA --------------ms000808030003080300030708--