after many tries and failures, i finally did it

i recently stumpled upon this very nice emailwiz script from LukeSmithxyz on github. Inspired by that, i gave setting up my own mailserver another try. It was surprisingly simple, it is running for weeks now and i had no troubles so far.

modification

i modified the script a little bit more included the certbot stuff and patched some stuff i found on the github issues pages. Github link: install-email neue version

multiple mailboxes and domains

for this i had browse the web a little while and found this 2 useful resources postfix virtual and linuxbabe.

  1. you have to add a new unix user for each mailbox 
     useradd -m -G mail newaccount
 passwd newaccount
  2. expand the ssl certificate, you need to have the A and CNAME dns record working for the SSL certificate, see 5. 
    certbot certonly --webroot --agree-tos --text --non-interactive --webroot-path /var/www/html -d mail.domain1.com,mail.domain2.org --expand
  3. generate the dkim keys and edit signingtable, keytable and trustedhosts. 
    opendkim-genkey -b 2048 -d domain2.org -D /etc/postfix/dkim/ -s mail-domain2 -v
chown opendkim:opendkim mail-domain2.private
echo "mail-domain2._domainkey.domain2.org domain2.org:mail-domain2:/etc/postfix/dkim/mail-domain2.private" >> /etc/postfix/dkim/keytable
echo "*.domain2.org" >> /etc/postfix/dkim/trustedhosts
echo "*@domain2.org mail-domain2._domainkey.domain2.org" >> /etc/postfix/dkim/signingtable
  4. edit the file /etc/postfix/virtual. for first time using more than 1 accounts you also need to configure postfix main.cf and add a file virtual. important! do not add you main domain domain1.com to your virtual_alias_domains. 
    postconf -e "virtual_alias_domains = domain2.org"
postconf -e "virtual_alias_maps = hash:/etc/postfix/virtual"
cat <<EOF
postmaster@domain1.com   postmaster
office@domain1.com       oldaccount
admin@domain1.com        oldaccount
postmaster@domain2.org   postmaster
info@domain2.org         newaccount
EOF > /etc/postfix/virtual
  5. add all the required dns record. reverse dns is not needed multiple times it is fine if your main domain works. note: replace 127.0.0.1 with your ip address. 
    A     domain2.org        "127.0.0.1"
A     mail.domain2.org   "127.0.0.1"
MX    domain2.org        "10 mail.domain2.org"
TXT   domain2.org        "v=spf1 mx a:mail.domain2.org -all"
TXT   _dmarc.domain2.org "v=DMARC1; p=reject; rua=mailto:dmarc@domain2.org; fo=1"

    the domainkey TXT record you can cat /etc/postfix/dkim/mail-domain2.txt. i shortened the rsa key, but it should look something like that:

    TXT mail-domain2._domainkey.domain2.org "v=DKIM1; h=sha256; k=rsa; \""
"p=MIIBIjANBgkqhkiG9WbcWfa2FgonIQH/HHEpK5nFF5yJ"
"X2McsrH0Bm4JvekHgUVQlpboNCCP2+m1UlFQML4wIDAQAB"

reload configuration afterwards

postmap /etc/postfix/virtual
postfix reload

mail client - mutt

i also use mutt for mail and i found this very nice mutt-wizard script also from LukeSmithxyz, for setting up the addresses. it is very well documented. you need to install neomutt for this to work properly.

links