Config postfix smarthost » Historie » Version 1
Jeremias Keihsler, 13.01.2017 12:07
1 | 1 | Jeremias Keihsler | h1. Setting up Postfix to send mails via external mail-account |
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2 | |||
3 | h2. Preliminary note |
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4 | |||
5 | See also: |
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6 | * https://www.zulius.com/how-to/set-up-postfix-with-a-remote-smtp-relay-host/ |
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7 | * http://rs20.mine.nu/w/2011/07/gmail-as-relay-host-in-postfix/ |
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8 | |||
9 | A typical email scenario: you're a developer, and you've got a development Linux box at home. You need to be able to send emails from your code or cron jobs, but you're too lazy to set up a full fledged email server on your LAN. Or you just want to use an email account provided by Google Apps, Yahoo, your ISP or in our case a iRedMail-installation. |
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10 | |||
11 | h2. Install postfix |
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12 | |||
13 | Should be preinstalled, as it is the default mail-handler with CentOS |
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14 | <pre><code class="bash"> |
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15 | yum install postfix cyrus-sasl cyrus-sasl-gssapi cyrus-sasl-plain |
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16 | </code></pre> |
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17 | |||
18 | h2. configure postfix |
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19 | |||
20 | <pre><code class="bash"> |
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21 | vim /etc/postfix/main.cf |
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22 | </code></pre> |
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23 | |||
24 | <pre> |
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25 | myorigin = example.com |
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26 | # Set this to your email provider's smtp server. |
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27 | # A lot of ISP's (ie. Cox) block the default port 25 |
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28 | # for home users to prevent spamming. So we'll use port 80 |
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29 | relayhost = mail.example.com:587 |
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30 | |||
31 | smtpd_sasl_auth_enable = yes |
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32 | smtpd_sasl_path = smtpd |
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33 | smtp_use_tls = yes |
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34 | smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd |
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35 | smtp_sasl_type = cyrus |
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36 | smtp_sasl_auth_enable = yes |
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37 | |||
38 | # optional: necessary if email provider uses load balancing and |
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39 | # forwards emails to another smtp server |
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40 | # for delivery (ie: smtp.yahoo.com --> smtp.phx.1.yahoo.com) |
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41 | smtp_cname_overrides_servername = no |
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42 | |||
43 | # optional: necessary if email provider |
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44 | # requires passwords sent in clear text |
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45 | smtp_sasl_security_options = noanonymous |
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46 | |||
47 | canonical_maps = hash:/etc/postfix/canonical |
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48 | </pre> |
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49 | |||
50 | additionally we need to know the server and email-address as well as the password to use |
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51 | <pre><code class="bash"> |
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52 | vim /etc/postfix/sasl_passwd |
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53 | </code></pre> |
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54 | |||
55 | <pre> |
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56 | mail.example.com:587 mailadr@example.com:password |
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57 | </pre> |
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58 | |||
59 | The above server hostname and port must exactly match the value for "relayhost" in /etc/postfix/main.cf. |
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60 | |||
61 | Generate a postfix lookup table from the previous file |
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62 | <pre><code class="bash"> |
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63 | postmap hash:/etc/postfix/sasl_passwd |
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64 | </code></pre> |
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65 | |||
66 | Test the lookup table, if all is good then the following will return the specified username:password |
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67 | <pre><code class="bash"> |
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68 | postmap -q mail.example.com:587 /etc/postfix/sasl_passwd |
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69 | </code></pre> |
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70 | |||
71 | next is to bind the local username to the email-address. You may also have a look into @/etc/aliases@ and check who's mail are sent to whom. |
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72 | <pre><code class="bash"> |
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73 | vim /etc/postfix/canonical |
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74 | </code></pre> |
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75 | |||
76 | <pre> |
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77 | root mailadr@example.com |
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78 | </pre> |
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79 | |||
80 | The above email-address must exactly match the email-address in sasl_passwd. |
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81 | |||
82 | Generate a postfix lookup table from the previous file |
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83 | <pre><code class="bash"> |
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84 | postmap hash:/etc/postfix/canonical |
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85 | </code></pre> |
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86 | |||
87 | Make sure that sasl_passwd and sasl_passwd.db files are readable/writeable only by root |
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88 | <pre><code class="bash"> |
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89 | chmod 600 /etc/postfix/sasl_passwd |
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90 | chmod 600 /etc/postfix/sasl_passwd.db |
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91 | </code></pre> |
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92 | |||
93 | Add postfix to be started at boot |
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94 | <pre><code class="bash"> |
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95 | chkconfig --add postfix |
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96 | </code></pre> |
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97 | |||
98 | h2. Test postfix |
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99 | |||
100 | Fire up Postfix |
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101 | <pre><code class="bash"> |
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102 | /etc/init.d/postfix start |
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103 | </code></pre> |
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104 | |||
105 | Test it out using sendmail alias from the command prompt |
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106 | <pre><code class="bash"> |
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107 | sendmail email@any.com |
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108 | Postfix is good to go. |
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109 | . |
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110 | </code></pre> |