Set up your mail server for sending

From Linuxintro
Revision as of 09:23, 18 April 2012 by imported>ThorstenStaerk (→‎Test it)

Overview

When you have set up a mail server you can by default send mails within your own domain (e.g. linuxintro.org) but not to the outside. What you probably want is that internet users can connect via a mail client, e.g. Thunderbird to your mail server. If they know a valid username and password, they are allowed to read and send mails.

Configure it

Authentication is done by saslauthd. So install saslauthd, in this case for SUSE Linux: 

yast -i cyrus-sasl-saslauthd

Start the service: 

/etc/init.d/saslauthd start

Make sure your authentication service is running: 

/etc/init.d/saslauthd status

has to deliver 

running

Make sure the service starts on boot 

chkconfig saslauthd on

In /etc/postfix/main.cf, set 

smtp_sasl_auth_enable = yes
smtpd_sasl_auth_enable = yes

In /etc/postfix/main.cf, add permit_sasl_authenticated to smtpd_recipient_restrictions. The resulting line may look like this: 

smtpd_recipient_restrictions = permit_mynetworks,
                               permit_sasl_authenticated,
                               reject_unauth_destination,
                               check_policy_service inet:127.0.0.1:60000

Restart Postfix 

/etc/init.d/postfix restart

Test it

# perl -MMIME::Base64 -e 'print encode_base64("myuser\0myuser\0mypassword");'
bXl1c2VyAG15dXNlcgBteXBhc3N3b3Jk
# telnet linuxintro.org 25
Trying 108.166.126.74...
Connected to linuxintro.org.
Escape character is '^]'.
220 mail.linuxintro.org ESMTP Postfix

Now you write 

EHLO hostname

Now the server responds like 

250-mail.linuxintro.org
250-PIPELINING
250-SIZE
250-VRFY
250-ETRN
250-AUTH LOGIN PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

Now you write 

AUTH PLAIN bXl1c2VyAG15dXNlcgBteXBhc3N3b3Jk

The server writes 

235 2.7.0 Authentication successful

This means it has worked. So write 

QUIT

And you see the response 

221 2.0.0 Bye
Connection closed by foreign host.

TroubleShooting

Authentication not enabled

Symptom

You get 

Sending failed: Your SMTP server does not support authentication. The server responded: "5.5.1 Error: authentication not enabled"
Solution

You will need to modify /etc/postfix/main.cf, set 

smtp_sasl_auth_enable = yes
smtpd_sasl_auth_enable = yes

and restart postfix: 

/etc/init.d/postfix restart

generic failure

Symptom

You get 

Sending failed. Most likely the password is wrong. The server responded: "5.7.8 Error: authentication failed: generic failure"
Solution

You need to make sure your authentication service has been started: 

/etc/init.d/saslauthd status

has to deliver 

running

no authentication mechanism available

Symptom

You get 

Sending failed: Your SMTP server does not support The server responded: "5.7.8 Error: authentication failed: no mechanism available"
Reson

You may have

  • plain
  • digest-md5
  • cram-md5

as authentication method in kmail.

Solution

Change this to Login.

no worthy mechanisms found

Symptom

You get 

Sending failed: An error occurred during authentication: SASL(-4):no mechanism available: No worthy mechs found
Reason

You may have

  • GSSAPI

as authentication method in kmail.

Solution

Change this to Login.

no mail is sent

Symptom

Nothing happens and no mail is sent

Reason

You may have

  • NTLM

as authentication method in kmail.

Solution

Change this to Login.

See also

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