E-Mail Tools David Hilley davidhi@cc.gatech.edu David Hilley, - - PowerPoint PPT Presentation

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E-Mail Tools David Hilley davidhi@cc.gatech.edu David Hilley, - - PowerPoint PPT Presentation

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E-Mail Tools David Hilley davidhi@cc.gatech.edu David Hilley, March 5, 2008 L A T EX - p. 1 Roadmap Introduction / Overview Roadmap Introduction Local Mail Utilities Local Mail Utilities & Configuration Mail Server

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SLIDE 1

David Hilley, March 5, 2008 L

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EX - p. 1

E-Mail Tools

David Hilley

davidhi@cc.gatech.edu

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SLIDE 2
  • Roadmap

Introduction Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

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EX - p. 2

Roadmap

■ Introduction / Overview ■ Local Mail Utilities & Configuration ■ Running Your Own Mail Server?

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SLIDE 3
  • Roadmap

Introduction

  • Email Pipeline/Components?
  • Lifecycle

Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 3

Introduction

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SLIDE 4
  • Roadmap

Introduction

  • Email Pipeline/Components?
  • Lifecycle

Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 4

Email Pipeline/Components?

■ MTA – Mail Transfer Agent (SMTP)

sendmail, qmail, Postfix, exim, Courier

■ MDA – Mail Delivery Agent

procmail, maildrop (or MTA)

■ Remote Access to delivered mail

POP3, IMAP , etc. Dovecot, Courier, Cyrus IMAP , SquirrelMail

■ MUA – Mail User Agent

Mutt, Gnus, Pine, etc.

■ Mail tools

Fetchmail, SpamAssassin, BogoFilter, etc.

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SLIDE 5
  • Roadmap

Introduction

  • Email Pipeline/Components?
  • Lifecycle

Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 4

Email Pipeline/Components?

■ MTA – Mail Transfer Agent (SMTP)

sendmail, qmail, Postfix, exim, Courier

■ MDA – Mail Delivery Agent

procmail, maildrop (or MTA)

■ Remote Access to delivered mail

POP3, IMAP , etc. Dovecot, Courier, Cyrus IMAP , SquirrelMail

■ MUA – Mail User Agent

Mutt, Gnus, Pine, etc.

■ Mail tools

Fetchmail, SpamAssassin, BogoFilter, etc.

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SLIDE 6
  • Roadmap

Introduction

  • Email Pipeline/Components?
  • Lifecycle

Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 5

Lifecycle

Local Machine

MTA MTA

SMTP

MDA MUA

Local Filters Local Files

Remote

MUA

Reads Outgoing

POP3 IMAP

Reads Reads IMAP

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SLIDE 7
  • Roadmap

Introduction

  • Email Pipeline/Components?
  • Lifecycle

Local Mail Utilities Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 5

Lifecycle

Local Machine

Outgoing

MTA

Host MTA

Outgoing SMTP

MDA MUA

Local Filters Local Files R e a d s

Fetchmail Host IMAP

IMAP

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SLIDE 8
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 6

Local Mail Utilities

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SLIDE 9
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 7

One Possible Configuration

■ Remote server gets/sends mail ■ Fetchmail – grabs mail to local machine ■ Procmail – delivers mail on local machine ■ SpamAssassin – filters spam ■ Local MTA “smart-hosts” to remote server

This is a useful configuration even if you run your own mail server, because you may want to fetch and store/read your mail locally on a desktop.

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SLIDE 10
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 8

Fetchmail

■ Two ways to run: ◆ From crontab/mail client/manually ◆ As daemon – supports IMAP IDLE

.fetchmailrc: poll email2.cc.gatech.edu with proto imap: user "davidhi" pass "12345678" is "davidhi" here keep mda "/usr/bin/procmail -d davidhi"; no rewrite ssl idle poll mikkeli.cc.gatech.edu with proto imap preauth ssh: plugin "ssh email 2> /dev/null"; user davidhi is davidhi here keep mda "/usr/bin/procmail -d davidhi"

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SLIDE 11
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 9

Procmail

■ Filters/sorts/pipes mail, etc. ■ Configure .procmailrc to specify mailboxes

and rules

MAILDIR=$HOME/.incoming DEFAULT=$HOME/.incoming/inbox LOGFILE=$PMDIR/log :0fw: spamassassin.lock * < 256000 | spamc :0: * ˆX-Spam-Status: Yes spam :0: * ˆX-GT-Spam-Rating: ######### spam :0: * ˆContent-Transfer-Encoding: base64 * name=.*\.(exe|bat|scr|pif|com) spam

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SLIDE 12
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 10

SpamAssassin

■ Two ways to run: ◆ Per-invocation ◆ spamc client / spamd daemon ■ system-wide config or

∼/.spamassassin/user prefs

required_hits 5 whitelist_from *@cc.gatech.edu blacklist_from *@microsoft.com rewrite_subject subject_tag [SPAM]

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SLIDE 13
  • Roadmap

Introduction Local Mail Utilities

  • One Possible Configuration
  • Fetchmail
  • Procmail
  • SpamAssassin
  • SpamAssassin Plugins

Mail Server Conclusion David Hilley, March 5, 2008 L

AT

EX - p. 11

SpamAssassin Plugins

■ ClamAV – detects malware attachments ■ DNS-BL – blacklists like SORBS, Spamhaus ■ DCC, Razor, Pyzor – distributed checksums ■ Hashcash, SPF ■ URI blacklists – SURBL.org ■ Bayesian filtering: BogoFilter or built-in: ◆ sa-learn ◆ use bayes 1 ◆ bayes auto learn 1

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SLIDE 14
  • Roadmap

Introduction Local Mail Utilities Mail Server

  • Potential Issues
  • Blueprint
  • Sender Policy Framework
  • DomainKeys

Conclusion David Hilley, March 5, 2008 L

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EX - p. 12

Mail Server

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SLIDE 15
  • Roadmap

Introduction Local Mail Utilities Mail Server

  • Potential Issues
  • Blueprint
  • Sender Policy Framework
  • DomainKeys

Conclusion David Hilley, March 5, 2008 L

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EX - p. 13

Potential Issues

■ Different game today due to spam ■ Caveats: ◆ Port 25 filtering ◆ Dynamic IP blacklists ◆ Reverse DNS doesn’t match:

e.g. c-69-180-23-68.hsd1.ga.comcast.net

◆ Slightly used IP – already in DNSBL

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SLIDE 16
  • Roadmap

Introduction Local Mail Utilities Mail Server

  • Potential Issues
  • Blueprint
  • Sender Policy Framework
  • DomainKeys

Conclusion David Hilley, March 5, 2008 L

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EX - p. 14

Blueprint

■ Set up a mail server: ◆ Postfix or exim ◆ qmail ◆ sendmail ■ Make an MX record for your domain ■ Set up SPF records ■ Set up DomainKeys/DKIM ■ Don’t forget a backup MX

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SLIDE 17
  • Roadmap

Introduction Local Mail Utilities Mail Server

  • Potential Issues
  • Blueprint
  • Sender Policy Framework
  • DomainKeys

Conclusion David Hilley, March 5, 2008 L

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EX - p. 15

Sender Policy Framework

■ Specifies who is allowed to send mail for a

certain domain.

mit.edu. 60 IN TXT "v=spf1 ip4:18.7.7.0/24 ip4:18.7.21.0/24 ip4:18.72.0.0/16 ˜all" ibm.com. 600 IN TXT "v=spf1 -all" us.ibm.com. 600 IN TXT "v=spf1 ip4:32.97.182.0/24 ip4:32.97.110.0/24 a:d25xlcore010.ca.ibm.com a:isource.boulder.ibm.com ˜all"

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SLIDE 18
  • Roadmap

Introduction Local Mail Utilities Mail Server

  • Potential Issues
  • Blueprint
  • Sender Policy Framework
  • DomainKeys

Conclusion David Hilley, March 5, 2008 L

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EX - p. 16

DomainKeys

■ Cryptographic signatures

in email header: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:s bh=...; b=...= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:con b=...= lookup selector._domainkey.domain: gamma._domainkey.gmail.com. 300 IN TXT "k=rsa\; t=y\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDIhyR3oItOy22ZOaBr

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SLIDE 19
  • Roadmap

Introduction Local Mail Utilities Mail Server Conclusion

  • Questions
  • Resources

David Hilley, March 5, 2008 L

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EX - p. 17

Conclusion

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SLIDE 20
  • Roadmap

Introduction Local Mail Utilities Mail Server Conclusion

  • Questions
  • Resources

David Hilley, March 5, 2008 L

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EX - p. 18

Questions Questions?

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SLIDE 21
  • Roadmap

Introduction Local Mail Utilities Mail Server Conclusion

  • Questions
  • Resources

David Hilley, March 5, 2008 L

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EX - p. 19

Resources

■ Fetchmail FAQ

http://catb.org/~esr/fetchmail/fetchmail-FAQ.html

■ Timo’s procmail tips and recipes

http://lipas.uwasa.fi/~ts/info/proctips.html

■ Sender Policy Framework: Project Overview

http://www.openspf.org/Project_Overview

■ DomainKeys Identified Mail (DKIM)

http://www.dkim.org

■ Postfix

http://www.postfix.org/

■ exim Internet Mailer

http://www.exim.org/

■ qmail homepage

http://www.qmail.org

■ Sendmail FAQ

http://www.sendmail.org/faq/