Inetone: VServer Postfix

Mailserver with postfix and dovecot (29.12.2020)#

Install with apt-get install postfix
Start reconfigure wizard with sudo dpkg-reconfigure postfix
Configuration

vi /etc/postfix/main.cf

example at vi /usr/share/postfix/main.cf.dist
list config settings with postconf -d

Check and restart

postfix check
sudo systemctl reload postfix
service postfix reload

Logs

vi /var/log/mail.log    <== (all levels)
vi /var/log/mail.info
vi /var/log/mail.warn
vi /var/log/mail.err

vi /etc/aliases

Dovecot #

„Mail Delivery Agent“ (MDA) for POP3 and IMAP.

based on tecadmin.net

apt-get install dovecot-core dovecot-lmtpd dovecot-imapd dovecot-pop3d
apt-get install dovecot-sieve dovecot-solr dovecot-antispam

vi /etc/dovecot/dovecot.conf
/etc/dovecot/conf.d
sudo systemctl enable dovecot.service
sudo systemctl start dovecot.service
sudo systemctl stop dovecot.service
sudo systemctl status dovecot.service

Adding users (03.02.2019)#

You can use any system account

adduser username

Note: to read those local emails in Linux check file /var/mail/<username>
or use command "mail", to be installed with "apt-get install mailutils".

or
Virtual Domain at /etc/postfix/virtual

1. You should have a virtual domain, exclude this at "mydestination", see Postfix guide

vi /etc/postfix/main.cf
    virtual_alias_domains = example.com, example2.com, ...
    virtual_alias_maps = hash:/etc/postfix/virtual

2. create a addresses file (/etc/postfix/virtual)

vi /etc/postfix/virtual
    postmaster@example.com postmaster
    info@example.com       joe
    sales@example.com      jane
    # Uncomment entry below to implement a catch-all address
    # @example.com         jim
    ...virtual aliases for more domains...
    
postmap /etc/postfix/virtual
postmap /etc/postfix/vmailbox
postfix reload
postfix stop
postfix start
newaliases
service postfix restart
postsuper -d ALL  <= delete all mails in queue
vi /var/log/mail.log
grep postfix /var/log/syslog

Virtual alias Domain vs virtual mailbox domain#

Virtual alias domains are not to be confused with the virtual mailbox domains that are implemented with the Postfix virtual(8) mail delivery agent. With virtual mailbox domains, each recipient address can have its own mailbox. With a virtual alias domain, the virtual domain has its own user name space.

vi /etc/postfix/main.cf
    virtual_mailbox_domains = example.com
    virtual_mailbox_base = /var/mail/vhosts   <= base folder fo all mailboxes
    virtual_mailbox_maps = hash:/etc/postfix/vmailbox <= subdirectories per mailbox
    virtual_minimum_uid = 100  <= for safety
    virtual_uid_maps = static:5000 <= system user for all emails
    virtual_gid_maps = static:5000 <= system group for all emails
    virtual_alias_maps = hash:/etc/postfix/virtual <= email addresses

vi /etc/postfix/vmailbox <= assigned folders for each email
    info@example.com    example.com/info
    sales@example.com   example.com/sales/
    # Comment out the entry below to implement a catch-all.
    # @example.com      example.com/catchall

/etc/postfix/virtual:
    postmaster@example.com postmaster

Pop3 / IMAP#

to betested:

Postfix is able to deliver POP3, then each mail address need to be mapped to a linux user for a proper password
for IMAP you should use dovecot

Forward email with Postfix (Mailserver)#

Postfix is a mail server and it is used to forward mails to username@your-domain.de to any external account.
(Hint: It does not matter, if your-domain.de is a redirection to any other server like euve1234.vserver.de)

The postfix setup is described here,
but I had to modify it a little:
1. Installation

> su
> apt-get update
> apt-get install postfix
> postfix reload

2. Check

> postfix check
> nmap localhost -p 25
> telnet localhost 25
> postconf -d
> tail /var/log/mail.log

If nmap does not work, then install it first

> apt-get install nmap

3. Configure Postfix

vi /etc/postfix/main.cf

Add/replace at the top

myorigin=your-domain.de
myhostname=your-domain.de
relay_domains=your-domain.de

Extend

mydestination = your-domain.de, ...
mynetworks = 5.45.105.135/8 ...

Disable

# myorigin = /etc/mailname

Add/replace regarding SPAM rejection

# anti-spam: smtp restrictions
smtpd_recipient_restrictions = reject_invalid_hostname,
        reject_unknown_recipient_domain,
        reject_unauth_destination,
        reject_rbl_client sbl.spamhaus.org,
        permit
 
smtpd_helo_restrictions = reject_invalid_helo_hostname,
        reject_non_fqdn_helo_hostname,
        reject_unknown_helo_hostname
 
smtpd_client_restrictions = reject_rbl_client dnsbl.sorbs.net

Open Port 25 for the outside world

inet_interfaces = all

Save/Close main.cf and restart postfix (shell)

> service postfix restart

4. Setup email users

Edit /etc/aliases

# This means that anyuser@your-domain.de will be forwarded to mailuser@mailprovider.de
anyuser: mailuser@mailprovider.de

Hint: You should setup at least following email addresses

webmaster@<your-domain>
postmaster@<your-domain>
abuse@<your-domain>

Enter in shell:

> postconf -e "alias_maps=hash:/etc/aliases"
> newaliases
> postfix reload [or service postfix restart]

Disable email settings from your domain provider#

If your domain provider also offers a mail server for your domain, you should disable that one and create a so called MX-Record, where you put your own server name as mail server. At Strato it must also have an ending dot at the name (?).